Status: Research / Backlog Context: Extracted from archive_docs/checkpoint_2026-01-29/COMPREHENSIVE_SYNTHESIS.md. Renamed: Previously called "Visual Tombstones." Ghost Node is now the canonical user-facing term. The Rust lifecycle state NodeLifecycle::Tombstone is unchanged — it is a code-level enum variant, not a user-facing label.

When a user deletes a node, the graph structure (edges) is often lost, creating a hole in the mental map. Ghost Nodes preserve this structure without keeping the full node content — deleted-but-remembered placeholders that maintain graph topology.

"Use ghost nodes to preserve structure when removing items. When node deleted, show ghost edges (dashed/faded) to preserve knowledge of connections."

1. Refactoring: You delete a central hub node but want to remember what it connected.
2. History: "I know I had a link here yesterday."
3. Pruning: Cleaning up a graph without losing the topology.

• NodeState::Tombstone: A new lifecycle state (alongside Active/Warm/Cold).
• Payload: Retains id, position, title (optional), and edges. Drops url, thumbnail, favicon.
• Persistence: Tombstones are persisted but can be garbage collected after N days or explicit "Clear Tombstones" command.

• Node: Rendered as a faint, dashed outline or a small "X" marker. No fill.
• Edges: Connected edges render as dashed/faded lines (EdgeStyle::Ghost).
• Interaction: Non-interactive for navigation. Right-click to "Restore" or "Permanently Delete".

• "Show Deleted": A toggle in the Graph View settings (like "Show Archived").
• Default: Off (tombstones are invisible).
• On: Tombstones appear, revealing the "graveyard" of the graph.

• Badge Plan: Can reuse the #archive tag logic (dimmed rendering) but with a distinct visual style.
• Edge Traversal: Tombstones preserve traversal history even if the destination content is gone.

Defer until Graph UX Polish is complete. This is a high-value feature for long-term graph maintenance but adds visual noise if not handled carefully.