mcp: tools/list shows write tools to read-only callers #1446

What

Since #1441, a read-only token can call the MCP read tools over POST /mcp. Write tools return a tool error (isError: true). But tools/list still advertises every tool, so an agent may plan around tools it cannot use and only learn at call time.

Why

Filtering tools/list by access (uteke_mcp::READ_ONLY_TOOLS for Access::ReadOnly) gives read-only clients an accurate catalog. Before changing it, check what uteke-cloud's /mcp advertises to read-only keys so the two stay aligned (MCP is CORE).

Testing

Add a test: tools/list with Access::ReadOnly returns exactly the names in READ_ONLY_TOOLS (minus the dispatch alias uteke_room_document). Access::Full is unchanged.