Replace the streaming-json CLI + generated PreToolUse-hook Grok adapter with grok's native ACP mode (JSON-RPC 2.0 over stdio). Adds GrokACPBackend/GrokACPDecoder/GrokACPDecisionMapping (a near-twin of the Codex app-server adapter); generalizes CodexJSONRPC into a shared JSONRPCConnection (jsonrpc-header flag, default off so Codex is byte-identical, plus endNotifications); deletes GrokBuildBackend, GrokStreamDecoder, GrokHookConfig and strips the /grok-hook HTTP bridge from MCPApprovalServer. Claude and Codex are left native. Preserves conflict-lock parity, native resume (session/load), and the hermetic fake-grok contract test. Full suite: 525 tests green.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
