feat: migrate semantic search to pgvector + full-text search

Replace JSON-string embeddings with native pgvector(1536) storage and
add PostgreSQL full-text search (tsvector/GIN) with Reciprocal Rank Fusion
for hybrid keyword + semantic ranking.

Changes:
- NoteEmbedding.embedding: String → vector(1536) via pgvector
- NoteEmbedding: added updatedAt for reindex tracking
- Note: added tsv (tsvector) with auto-update trigger for FTS
- semantic-search.service: hybrid FTS + vector search with RRF fusion
- embedding.service: toVectorString() for pgvector SQL literals
- Removed JS-side cosine similarity loops (now DB-side via <=>)
- Added HNSW index on NoteEmbedding.embedding (cosine distance)
- Added GIN index on Note.tsv for FTS queries

Schema migration in: prisma/migrations/20260512120000_pgvector_and_fts_search/

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

architectural-grid10/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "react-example",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite --port=3000 --host=0.0.0.0",
+    "build": "vite build",
+    "preview": "vite preview",
+    "clean": "rm -rf dist",
+    "lint": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@google/genai": "^1.29.0",
+    "@tailwindcss/vite": "^4.1.14",
+    "@vitejs/plugin-react": "^5.0.4",
+    "lucide-react": "^0.546.0",
+    "react": "^19.0.1",
+    "react-dom": "^19.0.1",
+    "vite": "^6.2.3",
+    "express": "^4.21.2",
+    "dotenv": "^17.2.3",
+    "motion": "^12.23.24"
+  },
+  "devDependencies": {
+    "@types/node": "^22.14.0",
+    "autoprefixer": "^10.4.21",
+    "tailwindcss": "^4.1.14",
+    "tsx": "^4.21.0",
+    "typescript": "~5.8.2",
+    "vite": "^6.2.3",
+    "@types/express": "^4.17.21"
+  }
+}