Drops the xfail now that Reduced-Field Synthesis (ADR-0027) maps every
20.0.0 cert; the corpus test holds the whole bucket to a strict 1000/1000.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Move the EpcClientService package (client + _retry + exceptions + tests) from
the dying backend/ tree to infrastructure/epc_client/ as the New-EPC-API Fetcher;
update the two callers (address2UPRN, a script). All 14 client tests pass.
Add SolarRepository port + SolarPostgresRepository persisting Google Solar
building insights as JSONB (solar_building_insights table), one row per Property.
The EPC repo half of this slice already landed in #1129. pyright strict clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
