[adapters] FastMCP Catalog bridge — auto-ingest tools from FastMCP servers

[dgenio]

Problem

FastMCP is the dominant MCP framework, powering ~70% of MCP servers and downloaded a million times a day. Currently, there is no direct way to load a FastMCP server's tool list into contextweaver's Catalog — users must manually convert each tool definition. This friction blocks adoption among FastMCP users.

Related: #87 tracks a narrower FastMCP CodeMode adapter; this issue covers the broader catalog bridge.

Proposal

Add adapters/fastmcp.py with utilities to bridge FastMCP servers and contextweaver Catalogs:

1. fastmcp_tools_to_catalog(tools) — Convert a list of FastMCP tool definitions to SelectableItems and register in a Catalog, preserving namespaces (FastMCP uses namespace_toolname convention)
2. load_fastmcp_catalog(server_url_or_config) — Connect to a running FastMCP server via MCP tools/list, convert all tools, and return a populated Catalog
3. Namespace inference — Detect FastMCP namespace prefixes (e.g., github_search_repos → namespace=github, name=search_repos)
4. Tag mapping — Map FastMCP tool tags to SelectableItem.tags for tag-based filtering

Dependency strategy

• Core conversion functions work with plain dicts (no FastMCP import needed)
• Add contextweaver[fastmcp] optional extra for live server discovery
• Keep the adapter usable without the extra by accepting tool definitions as dicts

Acceptance Criteria

• fastmcp_tools_to_catalog() converts FastMCP tool definitions to Catalog items
• Namespace prefixes correctly inferred from FastMCP naming convention
• Tags, descriptions, and schemas preserved during conversion
• contextweaver[fastmcp] optional extra defined in pyproject.toml
• Live server discovery works when FastMCP is installed (via tools/list)
• Core dict-based conversion works without FastMCP installed
• Tests cover namespace inference, tag mapping, and schema preservation
• Example recipe added (or cross-referenced from cookbook issue)

Implementation Notes

• FastMCP composition docs: https://gofastmcp.com/servers/composition
• Namespace convention: {namespace}_{tool_name} (underscore-delimited)
• Reuse mcp_tool_to_selectable() internally — add namespace extraction on top
• Consider #43 (MCP namespace inference) overlap — this issue supersedes it for FastMCP

File Paths

• src/contextweaver/adapters/fastmcp.py (new)
• src/contextweaver/adapters/__init__.py (edit — re-export)
• pyproject.toml (edit — add fastmcp optional extra)
• tests/test_adapters.py (edit — add FastMCP tests)
• examples/ (edit or new — FastMCP integration example)

Cross-references

• Related to [adapters] FastMCP CodeMode custom-discovery-tool adapter + example #87 (FastMCP CodeMode adapter — narrower scope)
• Related to [adapters] Add MCP namespace inference to mcp_tool_to_selectable() #43 (MCP namespace inference — subsumed for FastMCP case)