fix(extractor): capture all 17 openable §11 windows on cert 001431

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>

backend/documents_parser/elmhurst_extractor.py

@@ -1,6 +1,6 @@
 import re
 from datetime import date, datetime
-from typing import List, Optional
+from typing import Final, List, Optional
 
 from datatypes.epc.surveys.elmhurst_site_notes import (
     AlternativeWall,
@@ -811,6 +811,19 @@ class ElmhurstSiteNotesExtractor:
         r"^(\d+\.\d+)\s+(\d+\.\d+)\s+(\d+\.\d+)(?:\s+(\S.*?))?$"
     )
     _MANUFACTURER_RE = re.compile(r"^(Manufacturer|Default)\s+(\d+\.\d+)$")
+    # "Known data" rows (BFRC / SAP Table) lodge the §11 Data-Source cell on
+    # its own layout line with the U-value following on the next line — and
+    # carry no Frame Type / Frame Factor / Glazing Gap cells. The joined
+    # "<source> <U>" `_MANUFACTURER_RE` shape never matches them, so they are
+    # anchored by this standalone form instead (cert 001431 §11 has one
+    # "BFRC data" window). "Manufacturer"/"Default" are kept here only for
+    # symmetry; in practice they always join with the U-value above.
+    _STANDALONE_DATA_SOURCE_RE = re.compile(
+        r"^(BFRC data|BFRC|SAP Table|Assessor|Manufacturer|Default)$"
+    )
+    # RdSAP 10 §3.7 default window frame factor, used for "known data" rows
+    # that lodge U and g directly and omit the frame-factor cell.
+    _DEFAULT_FRAME_FACTOR: Final[float] = 0.7
     _ORIENTATION_TOKENS = frozenset({
         "North", "South", "East", "West", "NE", "NW", "SE", "SW",
     })
@@ -900,7 +913,10 @@ class ElmhurstSiteNotesExtractor:
 
     def _find_manufacturer_after(self, lines: List[str], data_idx: int) -> Optional[int]:
         for j in range(data_idx + 1, min(data_idx + 12, len(lines))):
-            if self._MANUFACTURER_RE.match(lines[j].strip()):
+            stripped = lines[j].strip()
+            if self._MANUFACTURER_RE.match(stripped) or (
+                self._STANDALONE_DATA_SOURCE_RE.match(stripped)
+            ):
                 return j
         return None
 
@@ -985,6 +1001,20 @@ class ElmhurstSiteNotesExtractor:
         # would-be glazing-prefix scan.
         inline_glazing_type = anchor.group(4) if anchor.lastindex and anchor.lastindex >= 4 else None
 
+        # The data-source line is either the joined "Manufacturer 4.80" shape
+        # (source keyword + U on one line) or a sparse standalone "BFRC data"
+        # / "SAP Table" shape (keyword alone, U on the next line, and no frame
+        # cells lodged). Resolve which up front: a sparse row has no frame
+        # type/factor to parse.
+        data_source_line = lines[manuf_idx].strip()
+        joined_match = self._MANUFACTURER_RE.match(data_source_line)
+        standalone_match = (
+            None if joined_match is not None
+            else self._STANDALONE_DATA_SOURCE_RE.match(data_source_line)
+        )
+        if joined_match is None and standalone_match is None:
+            return None
+
         # frame_type and frame_factor immediately follow the data line.
         # Layout-style cell joining sometimes collapses them onto a
         # single "Wood 0.70" line; treat both shapes uniformly so the
@@ -992,9 +1022,15 @@ class ElmhurstSiteNotesExtractor:
         # field (glazing_gap / bp / location / orient).
         if data_idx + 1 >= len(lines):
             return None
-        frame_type, frame_factor, middle_start = self._parse_frame_type_and_factor(
+        if standalone_match is not None:
-            lines, data_idx
+            # Sparse "known data" row: no frame type/factor/glazing-gap cells;
-        )
+            # everything between W×H×A and the data-source is location/orient.
+            frame_type, frame_factor = None, self._DEFAULT_FRAME_FACTOR
+            middle_start = data_idx + 1
+        else:
+            frame_type, frame_factor, middle_start = self._parse_frame_type_and_factor(
+                lines, data_idx
+            )
         if frame_factor is None or not 0.0 < frame_factor <= 1.0:
             return None
 
@@ -1017,28 +1053,40 @@ class ElmhurstSiteNotesExtractor:
             (t for t in middle if t in self._ORIENTATION_TOKENS), None
         )
 
-        # Manufacturer line carries data_source + u_value.
+        # Data-source line carries the source keyword and U-value: joined on
-        manuf_match = self._MANUFACTURER_RE.match(lines[manuf_idx].strip())
+        # one line ("Manufacturer 4.80") or, for sparse rows, the keyword alone
-        if manuf_match is None:
+        # with the U-value on the next line ("BFRC data" / "1.00"). `post_idx`
-            return None
+        # is where g_value / draught / shutters begin in either layout.
-        data_source = manuf_match.group(1)
+        if joined_match is not None:
-        u_value = float(manuf_match.group(2))
+            data_source = joined_match.group(1)
+            u_value = float(joined_match.group(2))
+            post_idx = manuf_idx + 1
+        else:
+            assert standalone_match is not None
+            data_source = standalone_match.group(1)
+            if manuf_idx + 1 >= len(lines):
+                return None
+            try:
+                u_value = float(lines[manuf_idx + 1].strip())
+            except ValueError:
+                return None
+            post_idx = manuf_idx + 2
 
-        # Post-manufacturer: g_value, draught, shutters.
+        # Post-data-source: g_value, draught, shutters.
-        if manuf_idx + 3 >= len(lines):
+        if post_idx + 2 >= len(lines):
             return None
         try:
-            g_value = float(lines[manuf_idx + 1].strip())
+            g_value = float(lines[post_idx].strip())
         except ValueError:
             return None
-        draught_proofed = lines[manuf_idx + 2].strip().lower() == "yes"
+        draught_proofed = lines[post_idx + 1].strip().lower() == "yes"
-        permanent_shutters = lines[manuf_idx + 3].strip()
+        permanent_shutters = lines[post_idx + 2].strip()
 
         # Prefix / suffix tokens (variable count) carry the
         # glazing-type, building-part, and orientation strings split by
         # the layout preprocessor.
         before = [lines[j].strip() for j in range(before_start, data_idx) if lines[j].strip()]
-        after = [lines[j].strip() for j in range(manuf_idx + 4, after_end) if lines[j].strip()]
+        after = [lines[j].strip() for j in range(post_idx + 3, after_end) if lines[j].strip()]
 
         # Room-in-roof windows lodge their location as "Roof of Room in
         # Roof" (wrapped across the prefix/suffix blocks). Detect it, pull

datatypes/epc/domain/mapper.py

@@ -4116,6 +4116,14 @@ def _is_elmhurst_roof_window(
         _ELMHURST_BP_ROOF_TYPES_WITH_ROOFLIGHTS
     ):
         return True
+    # A window lodged on a wall is vertical by definition. The U-value
+    # backstop below only catches skylights whose location/BP gives no
+    # roof signal; without this guard a high-U *wall* window (e.g. an old
+    # "Double pre 2002" unit at U 3.1 / 3.4) is mis-routed to the roof-
+    # window list on U-value alone — cert 001431 §11 lodges two such
+    # External-wall windows that must remain vertical `sap_windows`.
+    if "wall" in (w.location or "").lower():
+        return False
     return w.u_value > _ELMHURST_ROOF_WINDOW_U_THRESHOLD