feat(prefetch): kalıcı vehicles.fully_fetched kolonu (güvenilir tamlık ölçümü)

Redis prefetch:complete:* 21g TTL'li → "% tam çekilmiş"i güvenilir ölçemiyorduk.
Migration 0034: vehicles'a fully_fetched (bool, default false) + fully_fetched_at
(ts) + index. incrementCompleted chain parça ile bitince kalıcı flag'i set eder
(Redis marker'a EK — operasyonel skip mantığı değişmedi). fully_fetched_at her
re-drill tamamlanışında güncellenir (son-doğrulanma). Idempotent SQL.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/api/src/database/schema/core.ts

@@ -419,10 +419,20 @@ export const vehicles = pgTable(
     market: varchar("market", { length: 100 }),
     rawData: jsonb("raw_data"),
     source: varchar("source", { length: 20 }).default("pl24").notNull(),
+    // Durable completeness marker: set true when the prefetch chain finishes with
+    // parts (see PrefetchWorkerService.incrementCompleted). Unlike the ephemeral
+    // Redis `prefetch:complete:*` marker (21-day TTL, operational skip logic) this
+    // never expires — it's the reliable "% fully fetched" measurement. `_at` tracks
+    // the last time completion was confirmed (re-set on each re-drill completion).
+    fullyFetched: boolean("fully_fetched").default(false).notNull(),
+    fullyFetchedAt: timestamp("fully_fetched_at", { withTimezone: true }),
     createdAt: timestamp("created_at", { withTimezone: true }).defaultNow().notNull(),
     updatedAt: timestamp("updated_at", { withTimezone: true }).defaultNow().notNull(),
   },
-  (table) => [uniqueIndex("vehicles_vin_unique_idx").on(table.vin)],
+  (table) => [
+    uniqueIndex("vehicles_vin_unique_idx").on(table.vin),
+    index("vehicles_fully_fetched_idx").on(table.fullyFetched),
+  ],
 );
 
 // ─── User Vehicles (junction — user ↔ shared vehicle) ─

apps/api/src/jobs/prefetch-worker.service.ts

@@ -841,6 +841,13 @@ export class PrefetchWorkerService implements OnModuleInit, OnModuleDestroy {
         // isFinished, so partially-fetched vehicles are never marked — they keep
         // getting gap-filled.
         await this.redis.set(this.completeKey(vehicleId), "1", COMPLETE_TTL_S);
+        // Durable completeness flag (never expires) — the reliable "% fully
+        // fetched" measurement, independent of the ephemeral Redis marker.
+        // Re-set on every re-drill completion so fullyFetchedAt tracks last-verified.
+        await this.db
+          .update(vehicles)
+          .set({ fullyFetched: true, fullyFetchedAt: new Date() })
+          .where(eq(vehicles.id, vehicleId));
       } else {
         await this.markNoResult(vehicleId);
       }