## Why
Cached MCP definitions can be supplied to inference without waiting for the
server to finish initializing.
## What changed
- Publish cached tools while startup is still in progress, clearing their
potentially stale read-only hint.
- Wait for the selected server to start before executing a tool call, then
prepare the call against the refreshed live binding.
- Keep cached tools visible in a binding even when no live client is available,
while rejecting attempts to prepare those calls.
## Testing
- Cover cached-tool visibility before startup and replacement with live tool
metadata afterward.
- Verify cached definitions reach inference before MCP initialization and that
calls unavailable in the live catalog return the expected model-visible
error.
GitOrigin-RevId: 3aae8f474c344ccdc5e08fe321bbad21d85bffd1
3bbf1fe757