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/opencode.py

@@ -1,6 +1,6 @@
 import os, sys, sqlite3, shutil
 from typing import Optional, Any, List
-from lib_py.agents.base import BaseAgentAdapter, DiscoveryContext
+from lib_py.agents.base import BaseAgentAdapter, DiscoveryContext, scan_names, db_rows_naming
 from lib_py.verify_session import workspace_key
 
 _PROVIDER_ENV_VARS = (
@@ -194,6 +194,13 @@ class OpenCodeAgentAdapter(BaseAgentAdapter):
                 sys.stderr.write(f"WARN: purge opencode db records failed: {e}\n")
         return purged
 
+    def residual_artifacts(self, uuid: str, ctx: DiscoveryContext) -> list:
+        # Issue #31: the purge leaves event-sourced rows (event, todo, ...);
+        # deleting those is not known to be safe, so they are reported.
+        found = scan_names(f"{ctx.home_dir}/.local/share/opencode", uuid)
+        return found + db_rows_naming(self._resolve_db(ctx), uuid, ("session_id", "aggregate_id"),
+                                      id_tables=(("session", "id"),))
+
     def spawn_spec(self, binary: str, session_uuid: str = "", use_wrapper: bool = False) -> str:
         return f"{binary} --auto --agent build"