Add governed SPW bathymetry analysis

docs/DATA_SOURCES.md

@@ -764,6 +764,13 @@ population queries therefore derive from one reviewed national edition rather
 than mutually incompatible regional imports. No edition is downloaded or
 promoted during application startup.
 
+The live national workspace contains one consistent Statbel population series
+for 2021-2025. The 2021-2024 geometry archives use the official
+`YYYY/MM/DD` situation-date notation and archive member names without a
+repeated CRS token; the fail-closed preflight normalizes only those documented
+format variants and still validates EPSG:31370, release year, schema, joins,
+totals, topology repairs and checksums.
+
 ## Wallonia PICC and Brussels UrbIS
 
 The official-vector registry exposes bounded, source-specific regional
@@ -792,7 +799,7 @@ profile numbers, measurement dates, available structured depth/width values
 and official document URLs. Scanned documents remain evidence; missing fields
 are not filled by fabricated OCR output.
 
-The following sources are audited but not yet operational:
+The following sources are audited:
 
 - MDK Dieptemodel Belgisch Continentaal Plat/Noordzee: 20 x 20 m continuous
   raster in LAT, exposed through WCS/WMTS. GeoIntel now has a strict-TLS,
@@ -800,8 +807,13 @@ The following sources are audited but not yet operational:
   `bathy.agentschapmdk.be` presents a certificate for `*.l27powered.eu`.
   Hostname validation therefore fails with `tls_error`; raster acquisition
   remains disabled and TLS verification cannot be bypassed.
-- SPW bathymetry of navigable waterways and reservoir lakes: 0.5 m bed
-  elevation and XYZ data in mDNG.
+- SPW bathymetry of navigable waterways and reservoir lakes: the official
+  2023-05-23 GeoTIFF release is operational through
+  `scripts/import_spw_bathymetry.py`. The operator pins SHA-256
+  `04122a1c5cecc7b77be025b580995d024545e82d8310e158b4c112f7fa5f8a6e`,
+  validates the EPSG:3812/Float32/0.5 m/-9999 contract, creates only a bounded
+  COG and persists it through the canonical dataset upload API. Values are
+  bed elevations in mDNG from surveys composed over 2019-2022.
 - Port of Antwerp-Bruges periodic soundings: catalog candidate pending a
   stable public machine contract.