feat(mcpedia): Phase 2 — semantic + hybrid search, tRPC/Hono API

- @mcpedia/embeddings: OpenRouter provider (9router /v1, encoding_format float),
  chunkText + embedChunks; EMBED_DIM=2048
- document_chunks table (real[] embedding) — pgvector NOT available on shared
  imrnes Postgres, so cosine is computed in-app (KB-scale fine); pgvector deferred
- indexer: chunk + embed + upsert per document
- @mcpedia/search: semanticSearch (cosine) + hybridSearch (FTS+cosine RRF)
- apps/api: Hono + tRPC v11 (6 procedures), serve on :4020
- MCP: semantic_search + hybrid_search tools (6 total)
- web: keyword/hybrid toggle; .env.example + README + PHASES updated

package.json

@@ -14,11 +14,14 @@
     "lint": "turbo run lint",
     "typecheck": "turbo run typecheck",
     "index": "bun run scripts/indexer.ts",
-    "mcp": "bun --cwd apps/mcp run start"
+    "mcp": "bun --cwd apps/mcp run start",
+    "api": "bun --cwd apps/api run dev"
   },
   "devDependencies": {
+    "@trpc/client": "^11.18.0",
+    "@types/node": "^26.2.0",
+    "prettier": "^3.3.0",
     "turbo": "^2.5.0",
-    "typescript": "^5.6.0",
-    "prettier": "^3.3.0"
+    "typescript": "^5.6.0"
   }
 }