Migrate novem.comments.MCP() to mcp 2.x

[bjornars]

novem.comments.MCP() targets the mcp v1 API. mcp 2.0.0 (published 2026-07-28) is a breaking release and the extra is pinned to <2 in #264 as a stopgap. This issue tracks the actual migration.

Verified breaking changes

Established by installing mcp==1.28.1 and mcp==2.0.0 side by side on Python 3.10 and comparing the surfaces novem actually uses:

	v1.28.1	v2.0.0
Server module	mcp.server.fastmcp	mcp.server.mcpserver (old path removed)
Server class	FastMCP	MCPServer
Tool schema attr	t.inputSchema	t.input_schema
call_tool() returns	tuple(list[Content], dict)	CallToolResult (not subscriptable)
Image content attr	item.mimeType	item.mime_type

What is not broken, so the migration surface is small: MCPServer(name) and .run(transport='stdio') keep compatible signatures, @server.tool() is unchanged, arbitrary attribute assignment (server.ctx = ...) still works, Image(data=, format=) still works, and v2 installs cleanly on Python 3.10.

Sites to change

• novem/comments.py:666 — from mcp.server.fastmcp import FastMCP
• novem/comments.py:887 — from mcp.server.fastmcp import Image
• novem/comments.py:808 — t.inputSchema raises AttributeError on v2
• novem/comments.py:669-670 — bare except ImportError swallows ModuleNotFoundError, producing the misleading "install the mcp extra" message when mcp is installed
• examples/mcp_mention_responder.py:110,173 — result[0] raises TypeError: 'CallToolResult' object is not subscriptable
• examples/mcp_mention_responder.py:180 — item.mimeType is missing on v2
• MCP() docstring references FastMCP (cosmetic)

Proposed approach

Support both majors rather than moving the pin to >=2. novem is a published library and third-party scripts may already be pinned to either major, so the extra should stay open at mcp>=1.0.0.

1. _check_mcp_deps() tries mcp.server.mcpserver first, falls back to mcp.server.fastmcp, and only reports "install the extra" when mcp itself is genuinely absent — distinguish a missing package from a moved symbol.
2. api_tools() reads getattr(t, "input_schema", None) or t.inputSchema.
3. Image import uses the same two-path fallback.
4. Update the example to normalize CallToolResult vs. tuple, and mime_type vs. mimeType.
5. Keep MCP()'s public signature and return contract unchanged.

Add CI coverage

This rotted silently because nothing exercises it: uv sync does not install optional extras and no test imports mcp. The lockfile bump in #263 would have gone green.

Add a job that installs the mcp extra and smoke-tests MCP(...).api_tools() against both majors — asserting the six tool names resolve is enough to catch every break listed above.