## Why
Selected plugin MCP servers may be skipped after the optional startup grace
period. When a user explicitly mentions a plugin or MCP server, the turn should
continue waiting so the requested tools are available to the model.
## What changed
- Track explicitly mentioned plugin IDs and MCP servers across later samples,
steered input, and same-turn restarts.
- Require matching selected-plugin MCP servers to finish startup before
capturing the tool catalog, while leaving unmentioned servers optional.
- Match `plugin://` identities independently of display names and ignore
targeting query parameters such as `app` and `browserFamily`.
## Testing
Added coverage for linked and structured plugin mentions, direct and batched
capability discovery, delayed environment attachment, steering, and same-turn
restarts.
GitOrigin-RevId: c509ef8df45df1a7edb0da6afdb2682dc53a4de8
460b63e5f4