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

apps/api/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "@mcpedia/api",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "bun run src/index.ts",
+    "start": "bun run src/index.ts",
+    "lint": "tsc --noEmit",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@hono/node-server": "^1.13.0",
+    "@mcpedia/config": "workspace:*",
+    "@mcpedia/core": "workspace:*",
+    "@trpc/server": "^11.0.0",
+    "hono": "^4.6.0",
+    "zod": "^3.23.8"
+  },
+  "devDependencies": {
+    "typescript": "^5.6.0"
+  }
+}

apps/api/src/index.ts

@@ -0,0 +1,26 @@
+import { serve } from "@hono/node-server";
+import { Hono } from "hono";
+import { fetchRequestHandler } from "@trpc/server/adapters/fetch";
+import { db } from "@mcpedia/db";
+import { appRouter } from "./router";
+import type { Context } from "./trpc";
+
+const app = new Hono();
+
+// Health check.
+app.get("/health", (c) => c.json({ ok: true }));
+
+// Mount tRPC at /trpc/*. The fetch adapter is the canonical Bun/Hono adapter.
+app.all("/trpc/*", (c) =>
+  fetchRequestHandler({
+    endpoint: "/trpc",
+    req: c.req.raw,
+    router: appRouter,
+    createContext: (): Context => ({ db }),
+  }),
+);
+
+const port = Number(process.env.API_PORT ?? 4020);
+serve({ fetch: app.fetch, port }, (info) => {
+  console.log(`MCPedia API listening on http://localhost:${info.port}`);
+});

apps/api/src/router.ts

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+import { z } from "zod";
+import { publicProcedure, router } from "./trpc";
+import {
+  getDocument,
+  getRelated,
+  hybridSearch,
+  keywordSearch,
+  listDocuments,
+  semanticSearch,
+} from "@mcpedia/core";
+
+export const appRouter = router({
+  search: publicProcedure
+    .input(z.object({ q: z.string(), limit: z.number().int().min(1).max(50).default(20) }))
+    .query(({ input }) => keywordSearch(input.q, input.limit)),
+
+  semanticSearch: publicProcedure
+    .input(z.object({ q: z.string(), limit: z.number().int().min(1).max(50).default(10) }))
+    .query(async ({ input }) => semanticSearch(input.q, input.limit)),
+
+  hybridSearch: publicProcedure
+    .input(z.object({ q: z.string(), limit: z.number().int().min(1).max(50).default(10) }))
+    .query(async ({ input }) => hybridSearch(input.q, input.limit)),
+
+  getDocument: publicProcedure
+    .input(z.object({ slug: z.string() }))
+    .query(async ({ input }) => getDocument(input.slug)),
+
+  listDocuments: publicProcedure
+    .input(z.object({ section: z.string().optional(), status: z.string().optional() }).optional())
+    .query(async ({ input }) => listDocuments(input ?? {})),
+
+  related: publicProcedure
+    .input(z.object({ slug: z.string(), limit: z.number().int().min(1).max(20).default(5) }))
+    .query(async ({ input }) => getRelated(input.slug, input.limit)),
+});
+
+export type AppRouter = typeof appRouter;

apps/api/src/trpc.ts

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+import { initTRPC } from "@trpc/server";
+import { db } from "@mcpedia/db";
+
+export interface Context {
+  db: typeof db;
+}
+
+export const t = initTRPC.context<Context>().create();
+
+export const router = t.router;
+export const publicProcedure = t.procedure;

apps/api/tsconfig.json

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+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "paths": {
+      "@mcpedia/db": ["../../packages/db/src/index.ts"],
+      "@mcpedia/db/schema": ["../../packages/db/src/schema.ts"],
+      "@mcpedia/*": ["../../packages/*"]
+    }
+  },
+  "include": ["src/**/*.ts"]
+}