feat(mcp): Streamable HTTP transport + deploy; secure restoreRevision

- apps/mcp/src/http.ts: serve MCP over Streamable HTTP (MCP 2025-03-26) on
  :4021, stateless mode (sessionIdGenerator undefined), CORS on /mcp. Remote
  clients can now call the 6 tools + 4 resources without a stdio subprocess.
- deploy/mcpedia-mcp.service: supervised systemd unit (MCP_PORT=4021).
- Caddy: mcp.asepharyana.my.id -> 4021; wiki. domain now also routes /trpc/*
  to the API (was swallowed by web -> tRPC was unreachable on the domain).
- apps/api: restoreRevision tRPC mutation now requires x-webhook-secret (the
  Web UI calls @mcpedia/core directly, so this only gates the open network
  endpoint). Threads the header into tRPC Context. Secures a state-changing
  action that was anonymously callable.
Verified live: https://mcp.asepharyana.my.id/mcp initialize/tools/list/
resources/list all 200; restoreRevision no-secret -> unauthorized, with-secret
-> handler; read-only tRPC reachable via domain.

package.json

@@ -17,6 +17,7 @@
     "enqueue": "bun run scripts/enqueue.ts",
     "worker": "/home/code/.bun/bin/bun --cwd apps/worker src/index.ts",
     "mcp": "bun --cwd apps/mcp run start",
+    "mcp:http": "/home/code/.bun/bin/bun --cwd apps/mcp src/http.ts",
     "api": "/home/code/.bun/bin/bun --cwd apps/api src/index.ts"
   },
   "devDependencies": {