perf(geoportal): 4-level UAT simplification + intravilan layer + preserve view on basemap switch

UAT zoom-dependent views (read-only, original geom NEVER modified):
- gis_uats_z0 (z0-5): 2000m simplification — country outlines
- gis_uats_z5 (z5-8): 500m — regional overview
- gis_uats_z8 (z8-12): 50m — county/city level with labels
- gis_uats_z12 (z12+): 10m — near-original precision

New layers:
- gis_administrativ (intravilan, arii speciale) — orange dashed, no simplification
- Toggle in layer panel (off by default)

Basemap switching:
- Now preserves current center + zoom when switching between basemaps

Parcels + buildings: NO simplification (exact geometry needed)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

prisma/gisuat-postgis-setup.sql

@@ -158,29 +158,49 @@ WHERE geometry IS NOT NULL AND geom IS NULL;
 CREATE INDEX IF NOT EXISTS gis_uat_geom_idx
   ON "GisUat" USING GIST (geom);
 
--- 8. Martin/QGIS-friendly view (moderate simplification — 50m tolerance)
-CREATE OR REPLACE VIEW gis_uats AS
-SELECT
-  siruta,
-  name,
-  county,
-  ST_SimplifyPreserveTopology(geom, 50) AS geom
-FROM "GisUat"
-WHERE geom IS NOT NULL;
+-- =============================================================================
+-- 8. Zoom-dependent views for Martin vector tiles
+--    4 levels of geometry simplification for progressive loading.
+--    SAFE: these are read-only views — original geom column is NEVER modified.
+-- =============================================================================
 
--- 9. Simplified view for low zoom levels (z5-z9) — 500m tolerance
-CREATE OR REPLACE VIEW gis_uats_simple AS
-SELECT
-  siruta,
-  name,
+-- z0-5: Very coarse overview (2000m tolerance) — country-level outlines
+CREATE OR REPLACE VIEW gis_uats_z0 AS
+SELECT siruta, name,
+  ST_SimplifyPreserveTopology(geom, 2000) AS geom
+FROM "GisUat" WHERE geom IS NOT NULL;
+
+-- z5-8: Coarse (500m tolerance) — regional overview
+CREATE OR REPLACE VIEW gis_uats_z5 AS
+SELECT siruta, name,
   ST_SimplifyPreserveTopology(geom, 500) AS geom
-FROM "GisUat"
-WHERE geom IS NOT NULL;
+FROM "GisUat" WHERE geom IS NOT NULL;
+
+-- z8-12: Moderate (50m tolerance) — county/city level
+CREATE OR REPLACE VIEW gis_uats_z8 AS
+SELECT siruta, name, county,
+  ST_SimplifyPreserveTopology(geom, 50) AS geom
+FROM "GisUat" WHERE geom IS NOT NULL;
+
+-- z12+: Fine (10m tolerance) — near-original precision
+CREATE OR REPLACE VIEW gis_uats_z12 AS
+SELECT siruta, name, county,
+  ST_SimplifyPreserveTopology(geom, 10) AS geom
+FROM "GisUat" WHERE geom IS NOT NULL;
+
+-- Keep the legacy gis_uats view for QGIS compatibility
+CREATE OR REPLACE VIEW gis_uats AS
+SELECT siruta, name, county,
+  ST_SimplifyPreserveTopology(geom, 50) AS geom
+FROM "GisUat" WHERE geom IS NOT NULL;
 
 -- =============================================================================
 -- Done! Martin serves these views as vector tiles:
---   - gis_uats        (moderate detail, z9+)
---   - gis_uats_simple (coarse overview, z5-z9)
--- QGIS: PostgreSQL -> 10.10.10.166:5432 / architools_db -> gis_uats view
+--   - gis_uats_z0    (z0-5,  2000m simplification)
+--   - gis_uats_z5    (z5-8,  500m)
+--   - gis_uats_z8    (z8-12, 50m)
+--   - gis_uats_z12   (z12+,  10m near-original)
+--   - gis_uats       (legacy for QGIS, 50m)
+-- Original geometry in GisUat.geom is NEVER modified.
 -- SRID: 3844 (Stereo70)
 -- =============================================================================