feat(collection): PostgreSQL 백킹 활성화 (CollectionRepository + TokenCache)

- Program.cs: PlaceholderCollectionRepository/TokenCache/KisApiClient → 실제 구현체로 변경
- 데이터베이스 초기화: EnsureTablesAsync() 호출 (시작 시 테이블 자동 생성)
- kis_tokens, kis_collection_runs, kis_collection_snapshots, kis_collection_errors 테이블
- Dapper 기반 SQL 쿼리 (파라미터화, SQL 주입 방지)
- 인덱스: started_at, ticker, captured_at, run_id
- PlaceholderImplementations.cs 제거

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/dotnet/QuantEngine.Web/bin/Debug/net10.0/QuantEngine.Web.runtimeconfig.json

@@ -0,0 +1,20 @@
+{
+  "runtimeOptions": {
+    "tfm": "net10.0",
+    "frameworks": [
+      {
+        "name": "Microsoft.NETCore.App",
+        "version": "10.0.0"
+      },
+      {
+        "name": "Microsoft.AspNetCore.App",
+        "version": "10.0.0"
+      }
+    ],
+    "configProperties": {
+      "System.GC.Server": true,
+      "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization": false,
+      "Microsoft.AspNetCore.Components.Endpoints.NavigationManager.DisableThrowNavigationException": true
+    }
+  }
+}