feat: add Geoportal module with MapLibre GL JS + Martin vector tiles

Phase 1 of the geoportal implementation:

Infrastructure:
- Martin vector tile server in docker-compose (port 3010)
- PostGIS setup SQL for GisUat: native geom column, Esri→PostGIS
  trigger, GiST index, gis_uats view for Martin auto-discovery

Geoportal module (src/modules/geoportal/):
- map-viewer.tsx: MapLibre GL JS canvas with OSM base, Martin MVT
  sources (gis_uats, gis_terenuri, gis_cladiri), click-to-inspect,
  zoom-level-aware layer visibility, layer styling
- layer-panel.tsx: collapsible sidebar with layer toggles
- geoportal-module.tsx: standalone page wrapper
- Module registered in config/modules.ts, flags.ts, i18n

ParcelSync integration:
- 6th tab "Harta" with lazy-loaded MapViewer (ssr: false)
- Centered on selected UAT

Dependencies: maplibre-gl v5.21.0

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

src/app/(modules)/geoportal/page.tsx

@@ -0,0 +1,33 @@
+"use client";
+
+import { FeatureGate } from "@/core/feature-flags";
+import { useI18n } from "@/core/i18n";
+import { GeoportalModule } from "@/modules/geoportal";
+
+export default function GeoportalPage() {
+  const { t } = useI18n();
+
+  return (
+    <FeatureGate flag="module.geoportal" fallback={<ModuleDisabled />}>
+      <div className="mx-auto max-w-7xl space-y-6">
+        <div>
+          <h1 className="text-2xl font-bold tracking-tight">
+            {t("geoportal.title")}
+          </h1>
+          <p className="text-muted-foreground">
+            {t("geoportal.description")}
+          </p>
+        </div>
+        <GeoportalModule />
+      </div>
+    </FeatureGate>
+  );
+}
+
+function ModuleDisabled() {
+  return (
+    <div className="mx-auto max-w-7xl py-12 text-center text-muted-foreground">
+      <p>Modulul Geoportal este dezactivat.</p>
+    </div>
+  );
+}