Refresh analytics cache after delete-staged completes

After deletion execution completes, automatically rebuild the Parquet
analytics cache with a full refresh. This ensures the cache reflects
updated deleted_from_source_at timestamps, so subsequent MCP queries
and TUI views correctly exclude deleted messages.

Fixes issue where stage_deletion would include already-deleted messages
because the Parquet cache was stale.

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

Author: robelkin-rational-partners

cmd/msgvault/cmd/deletions.go

@@ -472,6 +472,19 @@ Examples:
 		}
 
 		fmt.Println("\nDeletion complete!")
+
+		// Refresh analytics cache to reflect deleted messages
+		analyticsDir := cfg.AnalyticsDir()
+		if _, err := os.Stat(analyticsDir); err == nil {
+			fmt.Println("\nRefreshing analytics cache...")
+			if result, err := buildCache(dbPath, analyticsDir, true); err != nil {
+				fmt.Fprintf(os.Stderr, "Warning: failed to refresh cache: %v\n", err)
+				fmt.Fprintf(os.Stderr, "Run 'msgvault build-cache --full-rebuild' manually to update.\n")
+			} else if !result.Skipped {
+				fmt.Printf("Cache refreshed (%d messages).\n", result.ExportedCount)
+			}
+		}
+
 		return nil
 	},
 }