Add index_repo tool to MCP server

This tool allows creating/updating indexes dynamically from:
- GitHub repositories (requires owner and repo)
- GitLab repositories (requires project_id)
- BitBucket repositories (requires workspace and repo)
- Websites (requires url)

Features:
- Validates required parameters for each source type
- Checks if store supports write operations
- Refreshes runner state after indexing
- Invalidates cached client for updated indexes
- Returns success message with stats (type, filesIndexed, duration)

Agent-Id: agent-4dd9b0b4-3ecf-4a2a-850a-49fd55aba0b5

Author: richhankins

src/clients/mcp-server.ts

@@ -38,6 +38,7 @@ import {
   ListToolsRequestSchema,
 } from "@modelcontextprotocol/sdk/types.js";
 import type { IndexStoreReader, IndexStore } from "../stores/types.js";
+import type { Source } from "../sources/types.js";
 import { MultiIndexRunner } from "./multi-index-runner.js";
 import {
   SEARCH_DESCRIPTION,