feat(geoportal-v2): "S2" basemap — Sentinel-2 cloudless annual mosaics

Adds a 6th basemap option ("S2") backed by EOX's free, public,
CORS-open Sentinel-2 cloudless WMTS service. Annual mosaics from 2016
to 2024 (2025/2026 not yet shipped by EOX); 10 m/pixel resolution
good for large-scale rural change detection (deforestation,
greenhouses, halls, agriculture) but not for individual buildings.

Companion to the Wayback basemap shipped earlier — Wayback gives
high-res city detail at irregular snapshot dates, Sentinel-2 gives
predictable yearly cadence at coarse rural-scale resolution.

UI mirrors Wayback: when "S2" is selected the switcher reveals a year
dropdown beneath the basemap row; the map-viewer rebuilds the raster
source with the right EOX layer ID. Default year = latest (2024).

Note on licensing: EOX's 2018+ mosaics are CC BY-NC-SA 4.0 — non-
commercial. The UI surfaces this + the commercial-licence pointer
(cloudless.eox.at). 2016 (s2cloudless) + 2017 are CC BY 4.0, no
non-commercial restriction.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/modules/geoportal/v2/basemap-switcher.tsx

@@ -8,8 +8,15 @@ import {
   latestWaybackRelease,
   type WaybackRelease,
 } from "./wayback-catalog";
+import { SENTINEL_YEARS, type SentinelYear } from "./sentinel-catalog";
 
-export type BasemapId = "liberty" | "dark" | "satellite" | "google" | "wayback";
+export type BasemapId =
+  | "liberty"
+  | "dark"
+  | "satellite"
+  | "google"
+  | "wayback"
+  | "sentinel";
 
 const OPTIONS: Array<{ id: BasemapId; label: string }> = [
   { id: "liberty", label: "Liberty" },
@@ -17,6 +24,7 @@ const OPTIONS: Array<{ id: BasemapId; label: string }> = [
   { id: "satellite", label: "Satelit" },
   { id: "google", label: "Google" },
   { id: "wayback", label: "Istoric" },
+  { id: "sentinel", label: "S2" },
 ];
 
 interface Props {
@@ -26,6 +34,10 @@ interface Props {
   waybackReleaseId?: string | null;
   /** Fired when the user picks a different Wayback date. */
   onWaybackReleaseChange?: (release: WaybackRelease) => void;
+  /** Selected Sentinel-2 cloudless year (only meaningful when value=sentinel). */
+  sentinelYear?: string | null;
+  /** Fired when the user picks a different Sentinel-2 year. */
+  onSentinelYearChange?: (year: SentinelYear) => void;
 }
 
 export function BasemapSwitcher({
@@ -33,6 +45,8 @@ export function BasemapSwitcher({
   onChange,
   waybackReleaseId,
   onWaybackReleaseChange,
+  sentinelYear,
+  onSentinelYearChange,
 }: Props) {
   const [releases, setReleases] = useState<WaybackRelease[] | null>(null);
   const [loading, setLoading] = useState(false);
@@ -80,6 +94,36 @@ export function BasemapSwitcher({
         </div>
       </div>
 
+      {value === "sentinel" && (
+        <div className="rounded-md border bg-background/95 px-2 py-1.5 shadow-sm backdrop-blur">
+          <label className="flex items-center gap-1.5 text-[10px] font-medium uppercase tracking-wide text-muted-foreground">
+            <Clock className="h-3 w-3" />
+            An mosaic Sentinel-2
+          </label>
+          <select
+            value={sentinelYear ?? SENTINEL_YEARS[0]!.year}
+            onChange={(e) => {
+              const y = SENTINEL_YEARS.find((s) => s.year === e.target.value);
+              if (y && onSentinelYearChange) onSentinelYearChange(y);
+            }}
+            className="mt-1 w-full rounded border bg-background px-1.5 py-1 text-xs"
+          >
+            {SENTINEL_YEARS.map((y) => (
+              <option key={y.year} value={y.year}>
+                {y.year}
+                {y.year === "2016" ? " (+2017)" : ""}
+              </option>
+            ))}
+          </select>
+          <p className="mt-1 text-[9px] leading-tight text-muted-foreground">
+            Mozaic anual cloud-free Sentinel-2 (rezoluție ~10 m). Bun
+            pentru schimbări rurale large-scale (defrișări, hale,
+            sere). Nu vezi case sau detalii fine. © EOX / Copernicus.
+            Uz comercial: cloudless.eox.at.
+          </p>
+        </div>
+      )}
+
       {value === "wayback" && (
         <div className="rounded-md border bg-background/95 px-2 py-1.5 shadow-sm backdrop-blur">
           <label className="flex items-center gap-1.5 text-[10px] font-medium uppercase tracking-wide text-muted-foreground">