A GitHub connection's MCP tool can now point at GitHub's full endpoint
(/mcp/) instead of the read-only one when its owner opts in, at setup
(allow_writes) or later (PUT /api/connections/<id>/writes), which re-reads
the actions and keeps the choices for those on both endpoints. Actions from
the write endpoint are writes unless GitHub marks them read-only, so they
default to asking first.
Admins can forbid it per connector (allow_writes in Admin > Connectors,
kept in app_metadata). Then the option is refused, a refresh goes back to
read-only, and at run time the tool only ever calls the read-only endpoint
and write calls are denied with a reason.
