fix(grok): surface plan mode approval in proposed plan cards - #5409

💭 I'm checking the diff for Effect service conventions, focusing on GrokAdapter.ts, XAiAcpExtension.ts, and the associated tests and mock agent script. I want to verify how Schema is imported and used in XAiAcpExtension.ts.

1. browse_code — apps/server/src/provider/acp/XAiAcpExtension.ts

2. browse_code — apps/server/src/provider/Layers/GrokAdapter.ts

💭 This PR mostly concerns ACP extension helpers rather than new Effect services, and imports and error patterns look consistent with existing conventions. I check for stray mutable state and notice the GrokSessionContext follows an existing pattern already used elsewhere, and the const/type pairing for XAiExitPlanModeRequest looks like standard practice. I don't see any new Layer.succeed, ManagedRuntime.make, or runPromise calls, and no new errors were added. With no findings so far, this points toward an "All clear" verdict, though I need to reconcile that with the JSON output schema requirement — likely resolved by wrapping "All clear" as the summary within a success-state JSON response. Still, I want to double-check the GrokAdapter changes more closely, particularly the code around lines 540-580 and 745-800, for any subtle convention issues like Effect.catchTag usage or error wrapping.

3. browse_code — apps/server/src/provider/Layers/GrokAdapter.ts

4. browse_code — apps/server/src/provider/Layers/GrokAdapter.ts

💭 Everything here matches existing patterns, no new services or boundary issues. I do notice isGrokEnterPlanModeToolCall sits in GrokAdapter.ts while similar pure helpers live in XAiAcpExtension.ts, which is a minor file-layout inconsistency rather than a real convention violation, and there's also a duplicated isRecord helper worth flagging. Since there are no findings, I want to respond simply, but the schema requires structured JSON while the instructions also ask for the literal final response to be "All clear" on one line. I'll resolve that by producing minimal JSON with success state and "All clear" as the title and summary.