fix(agents): codex, grok and opencode report their residual (Issue #31)

Their purge is unchanged; what it leaves is now reported: codex names and
thread rows (state_*, thread_history_*; logs_* is not scanned), grok
memory-v2 observations, opencode event/todo rows. db_rows_naming opens the
DB read-only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.agents/skills/lib_py/agents/adapters/grok.py

@@ -1,7 +1,7 @@
 import os, json, glob, shutil
 from typing import Optional, Any
 from urllib.parse import quote
-from lib_py.agents.base import BaseAgentAdapter, DiscoveryContext
+from lib_py.agents.base import BaseAgentAdapter, DiscoveryContext, scan_names
 from lib_py.verify_session import workspace_key
 
 
@@ -108,6 +108,11 @@ class GrokAgentAdapter(BaseAgentAdapter):
             purged.append(self.artifact_path(uuid, ctx))
         return purged
 
+    def residual_artifacts(self, uuid: str, ctx: DiscoveryContext) -> list:
+        # Issue #31: reported, not removed - memory-v2 observations are the
+        # shared store of grok's memory pipeline.
+        return scan_names(f"{ctx.home_dir}/.grok", uuid)
+
     def spawn_spec(self, binary: str, session_uuid: str = "", use_wrapper: bool = False) -> str:
         if session_uuid:
             return f"{binary} --session-id {session_uuid} --permission-mode bypassPermissions"