fix(webhook): treat HTTP 409 (rebuild already running) as success, not error

The pmtiles-webhook returns 409 when a rebuild is already in progress.
Previously this was treated as a failure, showing 'Webhook PMTiles
indisponibil' error to the user. Now 409 is handled as a valid state
with appropriate messaging.

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

src/modules/parcel-sync/services/pmtiles-webhook.ts

@@ -9,10 +9,10 @@ const WEBHOOK_URL = process.env.N8N_WEBHOOK_URL || "";
 export async function firePmtilesRebuild(
   event: string,
   metadata?: Record<string, unknown>,
-): Promise<boolean> {
+): Promise<{ ok: boolean; alreadyRunning?: boolean }> {
   if (!WEBHOOK_URL) {
     console.warn("[pmtiles-webhook] N8N_WEBHOOK_URL not configured — skipping rebuild trigger");
-    return false;
+    return { ok: false };
   }
 
   try {
@@ -27,13 +27,17 @@ export async function firePmtilesRebuild(
     });
     if (res.ok) {
       console.log(`[pmtiles-webhook] Rebuild triggered (event: ${event}, HTTP ${res.status})`);
-      return true;
+      return { ok: true };
+    }
+    if (res.status === 409) {
+      console.log(`[pmtiles-webhook] Rebuild already running (event: ${event})`);
+      return { ok: true, alreadyRunning: true };
     }
     console.warn(`[pmtiles-webhook] Webhook returned HTTP ${res.status}`);
-    return false;
+    return { ok: false };
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
     console.warn(`[pmtiles-webhook] Failed: ${msg}`);
-    return false;
+    return { ok: false };
   }
 }