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/tips.go

@@ -154,7 +154,7 @@ func getLastShown(store storage.Storage, tipID string) time.Time {
 func recordTipShown(store storage.Storage, tipID string) {
 	key := fmt.Sprintf("tip_%s_last_shown", tipID)
 	value := time.Now().Format(time.RFC3339)
-	_ = store.SetMetadata(context.Background(), key, value)
+	_ = store.SetMetadata(context.Background(), key, value) // Non-critical metadata, ok to fail silently
 }
 
 // InjectTip adds a dynamic tip to the registry at runtime.