Pulls in 42 commits of calculator/mapper accuracy fixes from the per-cert
mapper-validation and floor/roof/heating fronts.
Conflict resolutions:
- mapper `_is_elmhurst_roof_window`: main dropped the branch's "wall location →
vertical" guard (it broke cert 000516's rooflight), but that re-broke cert
001431's two External-wall U>3.0 windows (which must stay vertical). The two
certs lodge a BYTE-IDENTICAL §11 row, so neither location nor U separates
them — the real discriminator is the room-in-roof context. Replaced the
unconditional U>3.0 backstop with one gated on the BP having a room-in-roof
(`_elmhurst_bp_has_room_in_roof`): 000516's Main BP has a "Room in roof type
1" (→ rooflight), 001431's does not (→ vertical). Validated against BOTH —
full Elmhurst worksheet suite 1038 pass + the 001431 window-extraction pin.
- property_postgres_repository: kept main's `ids_by_uprn` method + the branch's
`_restrictions_of` helper.
- sap_fuel.py: the branch relocated it to domain/billing/ (already carrying
main's to_table_32_code normalization), so kept the old path deleted.
Fallout from main's fabric fixes (validated by the boiler-3 real-cert pin which
still reproduces at delta 0):
- re-pinned the boiler-1 + boiler-instant-hw ASHP snapshot scores;
- main's §14.2 gas-boiler main-fuel derivation resolved the BGB/102 baseline
gap, so `test_gas_boiler_instant_hw_before_baselines` is now a passing test
(was an xfail tripwire).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A Summary §14.0 Table 4b gas boiler (SAP code 101-119) lodges no §14.0
"Fuel Type" string in the newer Elmhurst export. The carrier was resolved
only from §15.0 "Water Heating Fuel Type" — fine when the same boiler
heats the water, but a gas boiler paired with a SEPARATE electric
immersion lodges §15.0 "Electricity", so `_elmhurst_gas_boiler_main_fuel`
returned None and the cascade strict-raised MissingMainFuelType.
Cert 001431 boiler-1/boiler-2 "before" variants are exactly this config:
§14.0 SAP code 102/104 (mains-gas boiler), §15.0 electric immersion
(code 909), §14.2 Meters "Main gas: Yes". The meter flag is the
authoritative carrier signal — a 101-119 boiler on mains gas burns mains
gas — so adopt it (SAP10 main_fuel 26 per _ELMHURST_MAIN_FUEL_TO_SAP10
"Mains gas") when §15.0 can't disambiguate. §15.0 gas/LPG still wins when
present (keeps LPG-vs-mains-gas precision); no mains-gas meter + non-gas
§15.0 still strict-raises rather than guessing.
Spec: SAP 10.2 Table 4b "Seasonal efficiency for gas and liquid fuel
boilers" (PDF p.168), rows 101-119. Both certs now resolve main_fuel=26
and compute (was: hard raise).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A 440 mm (>420 mm) solid brick AS-BUILT wall computed U = 1.70 (the
220 mm bucket default) instead of the RdSAP-correct 1.10. The §5.7
Table 13 thickness path only fired for *insulated* brick (external/
internal + thickness > 0); the as-built case fell through to the
Table 6 cavity/solid age-band default.
Spec: RdSAP 10 Specification (9th June 2025), §5.7 "U-values for
uninsulated brick walls, age bands A to E", Table 13 (PDF p.40):
≤200 mm → 2.5, 200–280 mm → 1.7, 280–420 mm → 1.4, >420 mm → 1.1.
Table 6 footnote (b) on the "Solid brick as built" row (PDF p.40):
"Or from 5.7 if wall thickness is other than 200mm to 280mm" — the
thickness table supersedes the flat 1.7 default whenever a documentary
wall thickness is lodged (200–280 mm gives 1.7 either way). The §5.8 /
Table 14 dry-lining R is added on top only when the wall is dry-lined,
per the §5.7 closing sentence.
Validated against the user-generated Elmhurst worksheet "simulated
case 21" (replica of API cert 2818-3053-3203-2655-9204: mid-terrace,
age band B, solid brick as-built 440 mm, room-in-roof). New §3 cascade
pin `test_section_3_wall_u_by_thickness_case21_match_pdf` routes the
Summary through the real extractor + mapper and pins:
(31) 155.1000, (33) 175.6208, (36) 23.2650, (37) 198.8858 — all 1e-4.
External walls Main U → 1.1000; Sheltered RR gable → 1/(1/1.10+0.5) =
0.71 (was 0.92). Pinned on §3 only (case-6 precedent): its code-908
instantaneous multi-point gas water heater has a separate §4 (219) gap.
Cross-check: sim case 20 (220 mm) stays at 1.70 — unchanged.
API SAP accuracy (scripts/eval_api_sap_accuracy.py, 896 computed certs):
% |err| < 0.5 SAP vs lodged: 42.6% → 43.8%; mean |err| 2.045 → 2.010.
Regression: tests/domain/sap10_calculator/ (1861), backend/
documents_parser/tests/ (574), datatypes/epc/ + rdsap golden fixtures
all green (pre-existing test_total_floor_area excepted). pyright strict
net-zero. No solid-brick fixture pin shifted (200–280 mm unchanged).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A Detailed room-in-roof lodges "Stud Wall" surfaces, but the cascade billed
every one through Table 17 from its insulation — over-counting fabric on
internal studs that carry no heat loss. sim case 20's two studs lodge §8.1
Default U-value 0.00 and the P960 worksheet omits them from BOTH fabric heat
loss (§3: (33)=285.9847) and total exposed area (31)=239.68; the cascade
computed ~0.52 each → (33) +4.16 W/K and continuous SAP 43.05 vs 43.6322.
Gate the drop on the lodged Default U-value: 0.00 → internal knee wall,
return None (no heat loss, no area); positive → a real exposed knee wall
(cert 000565 Ext2 Detailed: 0.31 / 0.10) that still falls through to the
Table-17 path. The earlier over-broad "drop all studs" zeroed 000565's
genuine studs — this keeps them.
Pins test_summary_001431_case20_fabric_heat_loss_matches_worksheet_line_33
((33)=285.9847 at 1e-4); case 20 continuous SAP now EXACT (43.6322). 2850
pass (the lone test_total_floor_area failure is pre-existing on base);
pyright strict net-zero (32=32).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Sim case 20's §11 lodges 5 windows but only 1 surfaced. The "W H Area"
cells tokenize inconsistently: a narrow Area column keeps all three on one
line ("1.80 2.10 3.78" — matches _WIDTH_HEIGHT_AREA_RE), but a wider Area
column triggers pdftotext's 2+-space split, dropping the Area onto its own
line ("5.79 2.00" then "11.58"). The 3-decimal data anchor never matched
those four rows, so they were lost — gutting §6 solar gains (5 windows →
1) and dropping continuous SAP 43.05 → 38.32 vs the worksheet's 43.6322.
Pre-merge a "W H" line + a following lone-decimal Area into the canonical
"W H Area" line, gated on Area ≈ W × H (the §11 Area is always the product)
so a frame factor / g-value / U-value below a dimension line is never
absorbed. One-line layouts (3 decimals) are untouched.
Pins via test_summary_001431_case20_extracts_all_five_section11_windows
(Summary_001431_case20.pdf mirrors sap worksheets/golden fixture debugging/
simulated case 20/). 573 documents_parser tests pass; pyright strict net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
RdSAP 10 §2 (Ventilation, "Walls" row): "Structural infiltration: 0.25
for steel or timber frame or 0.35 for masonry construction ... System
build: treated as masonry." `_is_timber_or_steel_frame` wrongly included
wall_construction code 6 (system build) alongside code 5 (timber frame),
handing system-build dwellings the 0.25 structural ACH instead of 0.35.
On the cat-10 room-heater fixture (ref 001431, walls SY System Build →
code 6) this under-stated the infiltration rate (18) by exactly 0.10
(0.45 vs worksheet 0.55), dropping the effective air change (25), the
ventilation heat loss (38)m = 0.33 × (25)m × (5), and the heat-transfer
coefficient (39) — so space-heating demand (98) came out 404 kWh low
((211) 11158.6 vs worksheet 11563.2). Restrict the 0.25 branch to code 5
only; code 6 (and everything else) is masonry at 0.35.
Pins the rating-block (38)m ventilation heat loss mean = 83.3613 W/K at
abs 1e-4 and asserts the classifier treats the system-build wall as
masonry. §4 suite green (2415 passed, 1 skipped); no existing fixture
relied on system-build → 0.25.
Residual after this slice: SAP +0.03 / cost -£0.95 — a small fabric (33)
gap (-0.15 W/K) plus lighting (232) +1.0 kWh remain as separate causes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Water heating SAP code 909 (electric instantaneous) and 907 (single-point
gas) heat water at the point of use, serving one outlet with no
distribution pipework. Per SAP 10.2 §4 (p.23, l.1416): "'Single-point'
heaters, which are located at the point of use and serve only one outlet,
do not have distribution losses either." So worksheet (46)m = 0 and the
heat-required line collapses to SAP 10.2 worksheet l.7704
(62)m = 0.85 × (45)m + (46)m + (57)m + (59)m + (61)m
= 0.85 × (45)m (all loss terms zero for a no-cylinder system).
`distribution_loss_monthly_kwh` already supported the
`is_instantaneous_at_point_of_use` flag (and its docstring already named
codes 907/909), but `water_heating_from_cert` hard-coded it to False, so
the cascade applied (46)m = 0.15 × (45)m to single-point heaters. That
0.15 distribution loss exactly cancelled the 0.85 reduction, leaving
(62)m = (45)m. On the cat-10 room-heater fixture (ref 001431, code 909)
that over-stated the water fuel (219) as 2082.6250 instead of the
worksheet's 1770.2313, and inflated the (65)m heat gains (692.47 vs
worksheet 442.55) which in turn suppressed space-heating demand.
Thread the cert's existing instantaneous flag (`_INSTANTANEOUS_WATER_CODES`
= {907, 909}) through `_water_heating_worksheet_and_gains` into both the
demand-pass and final `water_heating_from_cert` calls.
Pins (219) water fuel = 1770.2313 at abs 1e-4 via the extractor → mapper →
rating cascade. §4 suite green (2414 passed, 1 skipped); no existing
fixture exercised the 907/909 path. The residual space-heating fuel gap
((211) 11158.59 vs worksheet 11563.17) this exposes is a separate cause —
next slice.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
cert 001431's §11 lodges 17 windows but only 14 surfaced, via two distinct gaps:
1. Extractor (_extract_windows_from_layout): the one "Double glazing, known
data" row whose §11 Data-Source cell is "BFRC data" was rejected — it is
laid out as a standalone keyword line with the U-value on the next line
and lodges no Frame Type/Factor/Gap cells, so it never matched the joined
"<source> <U>" Manufacturer-line shape. Now anchored by a standalone
data-source form, with the RdSAP 10 §3.7 default frame factor (0.7) for
the absent frame cell.
2. Mapper (_is_elmhurst_roof_window): the two "Double pre 2002" rows
(U 3.1 / 3.4 > 3.0) were reclassified as roof windows by the U-value
backstop even though both are lodged on an "External wall". A window
lodged on a wall is vertical by definition; guard the U-value backstop so
it only fires when location/BP give no roof signal.
With both closed: 17 sap_windows, 0 misrouted to sap_roof_windows.
Re-homed onto the mapper-validation line from feature/bill-derivation
(orig f68cea27); the modelling-only regression test
(tests/domain/modelling/test_window_extraction_001431.py) stays on
bill-derivation. KNOWN: the mapper guard breaks cert 000516's
test_summary_pdf_mapper_chain pins (W6 U=3.10 routing) — must be resolved
before this PRs to main.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The Modelling glazing overlay's draught-proofing recompute (RdSAP 10 §8.1 —
a count over openable windows + doors) needs every openable window captured
with its draught_proofed flag. cert 001431's §11 lodges 17 windows but only
14 surfaced, via two distinct gaps:
1. Extractor (_extract_windows_from_layout): the one "Double glazing, known
data" row whose §11 Data-Source cell is "BFRC data" was rejected — it is
laid out as a standalone keyword line with the U-value on the next line
and lodges no Frame Type/Factor/Gap cells, so it never matched the joined
"<source> <U>" Manufacturer-line shape. Now anchored by a standalone
data-source form, with the RdSAP 10 §3.7 default frame factor (0.7) for
the absent frame cell.
2. Mapper (_is_elmhurst_roof_window): the two "Double pre 2002" rows
(U 3.1 / 3.4 > 3.0) were reclassified as roof windows by the U-value
backstop even though both are lodged on an "External wall". A window
lodged on a wall is vertical by definition; guard the U-value backstop so
it only fires when location/BP give no roof signal. The backstop's only
pinned cert (000516 W6) hand-builds its sap_roof_windows and so is
unaffected.
With both closed: 17 sap_windows, 0 misrouted to sap_roof_windows, 14
draught-proofed — reconstructing Elmhurst's lodged 84% (16/19 = (14 windows
+ 2 doors) / (17 windows + 2 doors)). Full calculator + modelling +
orchestration suites green (1885 pass); the 2 glazing draught-proofing
xfails remain (the overlay recompute is the glazing agent's front).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
PR feedback (dancafc): `_parse_thickness_mm` handles a None input and
returns Optional[int], so its call-return locals — and the Optional[str]
raws they read from `_local_val` — read clearer when annotated. Annotates
`thickness_raw`/`ins_thickness_raw: Optional[str]` and
`thickness_mm`/`insulation_thickness_mm: Optional[int]` at all four call
sites (_wall_details_from_lines, _alternative_walls_from_lines,
_roof_details_from_lines, _floor_details_from_lines), plus the adjacent
`u_val_raw`/`default_u` Optional pair in _floor_details_from_lines for
consistency. Matches the project convention of typehinting call-return
locals. No behaviour change; pyright clean, 569 parser tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Completes the secondary-glazing family. S0380.235 mapped the unknown-data
(7) and normal-emissivity (11) secondary variants; the RdSAP-21.0.1
`glazed_type` enum also defines code 12 "secondary glazing, low
emissivity", whose Elmhurst §11 label "Secondary glazing - Low
emissivity" was unmapped and would strict-raise. Cascade code 12 carries
the same daylight/solar bucket as 7/11 (g_L=0.80, g⊥=0.76); the lodged
manufacturer U/g drive §3/§6. With this the double family (codes 1/2/3/
7/13 via their Elmhurst phrasings) and the secondary family (4/11/12) are
fully covered. Coverage test extended.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
RdSAP 10 §3.3: "As Main Wall: Yes" makes an extension inherit the main
dwelling's external wall CONSTRUCTION only — the party wall type is
lodged separately per building part in the Summary §7 block and may
differ. `_extract_extensions` was copying `main_walls.party_wall_type`
into the inherited WallDetails, so every extension reused the main's
party wall U.
On the double_glazing fixture (Summary_001431) the Main lodges party
"CU Cavity masonry unfilled" (SAP10 wall_construction 4 → u_party_wall
0.5) but the 1st Extension lodges "U Unable to determine" (→ 0 → RdSAP
default 0.25). Pre-fix both building parts used 0.5, inflating worksheet
(32) party-wall heat loss by 6.56 W/K (Ext1 26.25 m² × 0.25). After the
fix worksheet (32) is exact: ours 32.573 vs worksheet 32.5725.
Now reads the extension's own "Party Wall Type" from its §7 chunk,
falling back to the main's only when the extension lodges none. Adds a
fixture + test asserting Main=4 / Ext=0 with distinct u_party_wall.
Suite 2413 pass; no cohort regression.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The double_glazing recommendation fixture (Summary_001431) exercises every
RdSAP-21 §11 glazing lodging in one cert; five labels were missing from
`_ELMHURST_GLAZING_LABEL_TO_SAP10` and strict-raised `UnmappedElmhurstLabel`:
"Secondary glazing" -> 7 (Table 6b "secondary glazing", g_L 0.80)
"Secondary glazing - Normal emissivity" -> 11 (RdSAP-21 secondary normal-E, g_L 0.80)
"Triple pre 2002" -> 10 (triple pre-2002, g_L 0.70)
"Triple with unknown install date" -> 6 (generic triple glazed, g_L 0.70)
"Single glazing, known data" -> 15 (single known-data, g_L 0.90)
The glazing code's only cascade effect is the §5 (66)..(67) daylight factor
g_L in `_G_LIGHT_BY_GLAZING_CODE` (single 0.90 / double+secondary 0.80 /
triple 0.70); the lodged manufacturer U-value and solar_transmittance drive
§3 / §6 directly (`_g_perpendicular` prefers the lodged value). Codes are the
semantically-exact RdSAP-21 rows within the correct g_L bucket, kept distinct
for the strict-raise audit trail. Adds a full-coverage test over all 13
distinct labels. Suite 2413 pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Appendix G4 (PDF p.72-73). A PV diverter routes surplus PV
generation (the would-be export EPV,m × (1 − βm)) to an immersion heater
in the hot-water cylinder. Per G4 step 4:
SPV,diverter,m = EPV,m × (1 − βm) × 0.8 × fPV,diverter,storageloss
(0.8 = cylinder heat-acceptance; fPV,diverter,storageloss = 0.9 for the
higher storage temperature), clamped to ≤ (62)m + (63a)m, and entered as
the negative worksheet (63b)m (step 5). The β factor is computed on the
PRE-diverter (219) per the §3a note (lines 5485-5486). Effects:
- (64)m = (62)m + (63b)m → less main-system water-heating fuel (219);
- export drops to EPV,ex,m = EPV,m(1 − βm) + (63b)m / 0.9 (§4 p.94
line 5501); the onsite dwelling portion EPV,m × βm is unchanged.
Inclusion (G4 step 1) requires ALL of: a PV system connected to the
dwelling; a cylinder larger than (43) average daily HW use; no solar
water heating; no battery — else the diverter is disregarded.
Three layers:
- extractor reads Summary §19 "Diverter present"; schema 21.0.0/21.0.1
SapEnergySource gains `pv_diverter` (API `sap_energy_source.pv_diverter`);
- `Renewables.pv_diverter_present` + domain `SapEnergySource.pv_diverter_present`,
set in both the Elmhurst and API mapper paths;
- `_pv_diverter_monthly_kwh` applies the G4 math after the β split;
`cert_to_inputs` recomputes (219) and the PV export.
On simulated case 19 (electric storage heaters, 7-hour, PV + diverter):
SAP continuous 50.33 → 51.34 (worksheet 51.2221; both round to the
lodged 51), cost (255) 1847.5 → 1812.3 (ws 1816.6), CO2 (272) 3331 →
3120 (ws 3126), with (233a) dwelling 1280.6 (ws 1280.4). The residual
+0.11 SAP is an upstream winter Appendix-M monthly-EPV-shape gap +
fabric (33) +1.0, tracked as the next case-19 cause. Suite: 2412 pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The gov-EPC API mapper sets BOTH roof_construction (int) and
roof_construction_type (str, derived via _API_ROOF_CONSTRUCTION_TO_STR),
but the Elmhurst mapper set only the string — leaving roof_construction
None on every site-notes cert. The SAP cascade reads the STRING (so SAP
cross-mapper parity always held), but consumers of the int (e.g.
domain/sap10_ml/transform.py ML aggregates `main_dwelling_roof_
construction`) silently saw None on the Elmhurst path.
New `_elmhurst_roof_construction_int` maps the Elmhurst roof-type code to
the same SAP10 int the API lodges (F→1, PN→3, PA→4, PS→8, S/A→7),
harvested from the committed Summary fixtures. Unlike the wall map it
returns None (not a strict-raise) for unmapped codes: the int is not
cascade-load-bearing, so an unknown roof must not block the cert (vaulted
5 / thatched 6 / NR omitted until a fixture surfaces them).
The 6 hand-built U985 reference fixtures gain the matching
roof_construction int (4/4/3 etc.) so test_from_elmhurst_site_notes_
matches_hand_built_* still asserts structural parity. SAP output is
unchanged (cascade reads the string). §4 suite green (2407 passed); the
two pre-existing stone-§5.6 sap10_ml failures are unrelated/out of scope.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
RdSAP10 `wall_construction == 6` is canonically WALL_SYSTEM_BUILT — a
WALL TYPE — but the gov-EPC basement heuristic hijacked it: Elmhurst
lodges both "SY System build" and "B Basement wall" as code 6, and the
API lodges basements as code 6 too, so a system-built wall was
mis-flagged `main_wall_is_basement` → wrong RdSAP §5.17 / Table 23
u_basement_wall/u_basement_floor overrides, and downstream the solid-wall
Recommendation Generator couldn't offer EWI/IWI on system-built walls.
System-built stays the wall type on its canonical code 6; the basement
signal moves OFF code 6 to a dedicated `is_basement` (SapAlternativeWall)
/ `wall_is_basement` (SapBuildingPart) Optional[bool] flag:
- Elmhurst: `_elmhurst_wall_is_basement` sets it from the distinct
"SY"/"B" labels (False for SY, True for B, None otherwise).
- gov-EPC API: per-wall code 6 can't be told apart at lodging time, so
`from_api_response` post-processes via `_clear_basement_flag_when_
system_built` — when the cert addendum marks the dwelling system-built,
the code-6 basement heuristic is cleared. A genuine basement (no
addendum signal) keeps the code-6 fallback.
- `main_wall_is_basement` / `is_basement_wall` honour the flag when set,
else fall back to the code-6 heuristic — so untouched API basements and
the cert 000565 "B" cohort are unchanged.
`EpcPropertyData.system_build` is a derived property over the wall type:
the MAIN wall is system-built iff `wall_construction == 6` and it is not
flagged basement. System-built lives on `wall_construction`; the basement
attribute is separate.
Acceptance: a system-built main wall (Elmhurst SY, or API addendum
system_build) → wall_construction == 6, main_wall_is_basement is False,
system_build is True; a genuine basement main wall → main_wall_is_basement
is True, system_build is False. Full §4 suite green (2404 passed).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
RdSAP10 `wall_construction == 6` is canonically WALL_SYSTEM_BUILT, but
the gov-EPC basement heuristic hijacked it: Elmhurst lodges both "SY
System build" and "B Basement wall" as code 6, so a system-built wall
was mis-flagged `main_wall_is_basement` and routed to the RdSAP §5.17
`u_basement_wall` override instead of the system-built U-value table.
System-built stays on its canonical code 6; the basement signal moves
to an explicit `is_basement` (SapAlternativeWall) / `wall_is_basement`
(SapBuildingPart) Optional[bool] flag, set by the Elmhurst mapper from
the distinct "SY"/"B" codes via `_elmhurst_wall_is_basement` (True for
B, False for SY, None otherwise). The `main_wall_is_basement` /
`is_basement_wall` properties honour the flag when set and fall back to
the gov-EPC API code-6 heuristic when None — so the API path (basement
lodged as integer 6, no flag) and the cert 000565 "B" cohort are
unchanged.
Acceptance (a recommendation-summary generator depends on it): a
system-built MAIN wall reports wall_construction == 6 AND
main_wall_is_basement is False; a genuine basement main wall still
reports main_wall_is_basement is True.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The Summary-path mapper raised UnmappedElmhurstLabel for a §15.1
"Cylinder Insulation Type: Jacket" lodging — only "Foam" (→1, factory)
was mapped. SAP10 cylinder_insulation_type uses 2 for loose jacket
(matching the GOV.UK API codes), and SAP 10.2 Table 2 Note 1 gives it a
separate ~2× storage-loss factor that the cascade now handles
(S0380.224). Add "Jacket" → 2 for cross-mapper parity with the API path
and so the loose-jacket storage-loss branch fires on the Summary path.
Surfaced by simulated case 19 (a 210 L jacket cylinder + electric storage
heaters), which previously couldn't extract at all. §4 suite 2397 passed;
mapper.py pyright unchanged at 32.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
