* fix: MCP resource template URI expansion via prefix matching
Resource templates (RFC 6570 URI patterns like `db://tables/{table}/rows/{id}`)
were discovered from MCP servers but non-functional — `read_resource_sync()`
only accepted exact URIs from `_resource_map`, which excludes templates.
Add prefix-based fallback: extract the static prefix from each template
(everything before the first `{`), store a prefix→server mapping, and
fall back to longest-prefix matching when exact URI lookup fails. MCP
servers handle URI routing internally so we just need to route the
expanded URI to the correct server.
Also surface templates in the system message catalog and `/mcp` command
so the model knows they exist and can construct expanded URIs.
* fix: address PR #46 review feedback
- Template prefix collision now keeps more specific (longer) template
URI instead of blindly overriding
- Fix _match_template docstring to accurately describe startswith
matching on static prefixes (not full template matching)
- Add missing loop.close() in integration test finally block
- Rewrite test_template_longest_prefix_wins with genuinely different
prefix lengths to avoid brittle collision-order dependency
Patrick Buckley
8b2e2130fc