feat(api): MCP server endpoint — expose AI tools to external clients

Mount an MCP (Model Context Protocol) server at /api/v1/mcp in the
unified Hono API. External clients like Claude Desktop, Cursor, and
VS Code Copilot can discover and call all 29 Mana tools via the
standard MCP protocol.

Architecture:
- WebStandardStreamableHTTPServerTransport for Bun/Hono compatibility
- AI_TOOL_CATALOG → MCP tool definitions with JSON Schema (via Zod)
- Stateful sessions with Mcp-Session-Id header
- Auth via existing authMiddleware (JWT or API key)

Phase 1 scope: tools/list returns all 29 tools with schemas,
tools/call acknowledges with descriptive messages. Phase 2 will add
actual DB reads/writes via sync_changes.

Usage:
  Claude Desktop config:
  {"mcpServers": {"mana": {"url": "http://localhost:3060/api/v1/mcp"}}}

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/package.json

@@ -15,10 +15,12 @@
 	"dependencies": {
 		"@ai-sdk/openai-compatible": "^2.0.41",
 		"@mana/media-client": "workspace:*",
+		"@mana/shared-ai": "workspace:*",
 		"@mana/shared-hono": "workspace:*",
 		"@mana/shared-rss": "workspace:*",
 		"@mana/shared-storage": "workspace:*",
 		"@mana/shared-types": "workspace:^",
+		"@modelcontextprotocol/sdk": "^1.29.0",
 		"ai": "^6.0.154",
 		"drizzle-orm": "^0.38.0",
 		"hono": "^4.7.0",