docs: record live WALOUS validation

CHANGELOG.md

@@ -9,6 +9,11 @@
 
 ## Unreleased - Post-V1 capability completion (2026-07-19)
 
+- Completed live WALOUS 2020/2023 provisioning and fixed signed `int8` source
+  reads with nodata `-128` across acquisition, analysis and PNG rendering. A
+  dedicated regression now proves conversion to the persisted `uint8`/`255`
+  contract, and live PostGIS/API/browser checks confirm real Walloon overlays,
+  hectare metrics and two-epoch temporal comparison on the deployed image.
 - Added operational Walloon WALOUS 2020/2023 land-cover analysis: an
   allowlisted checksum-validating provisioner, bounded EPSG:3812 window
   persistence, semantic hectare metrics, governed map rendering and raster

docs/CODEX_EXECUTION_LOG.md

@@ -11097,3 +11097,44 @@ Live evidence:
 - coverage resolution is zone-correct for Brussels, Wallonia and all three
   Belgian maritime legal zones. Unimplemented WALOUS, Walloon raster and MDK
   acquisition stays explicitly `not_configured`.
+
+## 2026-07-22 - Live WALOUS provisioning and signed-raster correction
+
+Implemented and verified:
+
+- provisioned the official WALOUS 2020 and 2023 land-cover GeoTIFFs in the
+  live source cache, including source checksums, EPSG:3812 metadata and the
+  official class-code validation set `1,2,3,4,5,6,7,8,9,80,90`;
+- corrected masked reads of the signed `int8` 2023 source, whose official
+  nodata value is `-128`, by widening valid raster values before assigning the
+  internal `uint8` nodata value `255`; acquisition, persisted analysis and map
+  rendering now share the safe conversion;
+- added a regression test that exercises all official class codes through an
+  `int8`/`-128` source and verifies the derived `uint8`/`255` output contract;
+- removed the redundant downloaded 2020 archive after checksum-verified
+  provisioning while retaining the normalized source raster and report.
+
+Live release evidence:
+
+- the complete readiness gate passed with 1,097 backend tests and 31 frontend
+  tests, backend compile, API/documentation contract audit, frontend typecheck,
+  production build, Alembic head `202607160001` and all script checks;
+- commit `e15a8200fd5c21f95a8cc1f5d6fdc6c5cb2aae3c` was deployed as immutable AI
+  image `geointel-all-in-one:e15a8200fd5c21f95a8cc1f5d6fdc6c5cb2aae3c-ai`;
+- live migration smoke passed against embedded PostGIS 3.6 with the complete
+  required schema and exactly one Alembic head;
+- live 2023 acquisition created Dataset
+  `92561bc3-3f1c-4d30-b926-58dea7793e43`; the same test area measured 315.86 ha
+  total, including 110.91 ha forest, 7.57 ha water and 135.79 ha artificial
+  land, with full raster coverage;
+- live 2020 acquisition created Dataset
+  `bdd19377-bfc9-425c-a7d4-6ac71c02bc1f`; a persisted 2020-2023 comparison
+  returned two observations and seven class-aware metric comparisons;
+- the live browser on port 1202 rendered the 2023 WALOUS overlay and real
+  hectare metrics for a Walloon rectangle. The evolution workspace exposed
+  distinct dated observations and the browser console remained error-free.
+
+Known governed boundaries remain explicit: WALOUS covers Wallonia rather than
+all Belgium, no unstable 2018 artifact is accepted without a verifiable source
+checksum, and the current local building model is not represented as nationally
+trained or validated.