chore: code health review - test fix and error comments (bd-9g1z, bd-ork0)

- Remove TestFindJSONLPathDefault from .test-skip (now passes)
- Add explanatory comments to 24 ignored error locations in cmd/bd:
  - Cobra flag methods (MarkHidden, MarkRequired, MarkDeprecated)
  - Best-effort cleanup/close operations
  - Process signaling operations

Part of code health review epic bd-tggf.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/bd/daemon_lifecycle.go

@@ -303,7 +303,7 @@ func stopDaemon(pidFile string) {
 	}
 	
 	// Clean up stale artifacts after forced kill
-	_ = os.Remove(pidFile)
+	_ = os.Remove(pidFile) // Best-effort cleanup, file may not exist
 	
 	// Also remove socket file if it exists
 	if _, err := os.Stat(socketPath); err == nil {