feat(parcel-sync): server-side eTerra session + auto-connect on UAT typing

- Add session-store.ts: global singleton for shared eTerra session state
  with job tracking (registerJob/unregisterJob/getRunningJobs)
- Add GET/POST /api/eterra/session: connect/disconnect with job-running guard
- Export routes: credential fallback chain (body > session > env vars),
  register/unregister active jobs for disconnect protection
- Login route: also creates server-side session
- ConnectionPill: session-aware display with job count, no credential form
- Auto-connect: triggers on first UAT keystroke via autoConnectAttempted ref
- Session polling: all clients poll GET /api/eterra/session every 30s
- Multi-client: any browser sees shared connection state

src/app/api/eterra/export-layer-gpkg/route.ts

@@ -8,6 +8,11 @@ import {
   clearProgress,
   setProgress,
 } from "@/modules/parcel-sync/services/progress-store";
+import {
+  getSessionCredentials,
+  registerJob,
+  unregisterJob,
+} from "@/modules/parcel-sync/services/session-store";
 
 export const runtime = "nodejs";
 export const dynamic = "force-dynamic";
@@ -21,8 +26,14 @@ type ExportLayerRequest = {
 };
 
 const validate = (body: ExportLayerRequest) => {
-  const username = String(body.username ?? "").trim();
-  const password = String(body.password ?? "").trim();
+  // Priority: request body > session store > env vars
+  const session = getSessionCredentials();
+  const username = String(
+    body.username || session?.username || process.env.ETERRA_USERNAME || "",
+  ).trim();
+  const password = String(
+    body.password || session?.password || process.env.ETERRA_PASSWORD || "",
+  ).trim();
   const siruta = String(body.siruta ?? "").trim();
   const layerId = String(body.layerId ?? "").trim();
   const jobId = body.jobId ? String(body.jobId).trim() : undefined;
@@ -122,6 +133,7 @@ export async function POST(req: Request) {
     const body = (await req.json()) as ExportLayerRequest;
     const validated = validate(body);
     jobId = validated.jobId;
+    if (jobId) registerJob(jobId);
     pushProgress();
 
     const layer = findLayerById(validated.layerId);
@@ -245,6 +257,7 @@ export async function POST(req: Request) {
     pushProgress();
     scheduleClear(jobId);
 
+    if (jobId) unregisterJob(jobId);
     const filename = `eterra_uat_${validated.siruta}_${layer.name}.gpkg`;
     return new Response(new Uint8Array(gpkg), {
       headers: {
@@ -260,6 +273,7 @@ export async function POST(req: Request) {
     note = undefined;
     pushProgress();
     scheduleClear(jobId);
+    if (jobId) unregisterJob(jobId);
     const lower = errMessage.toLowerCase();
     const statusCode =
       lower.includes("login failed") || lower.includes("session") ? 401 : 400;