Add dependency chain visualization #33
Description
Summary
Show the full dependency chain for a selected node - all upstream producers and downstream consumers.
Use Cases
- "What happens if this module goes down?"
- "Where does this module's input come from?"
- "Which modules depend on this output?"
- Impact analysis for changes
Proposed Features
Upstream Dependencies
- All nodes that (directly or transitively) produce data consumed by selected node
- Depth indicator (1st order, 2nd order, etc.)
- Path highlighting from sources to selected node
Downstream Dependents
- All nodes that (directly or transitively) consume data from selected node
- "Blast radius" - how many modules affected if this one fails
- Path highlighting from selected node to sinks
Visualization
- Fade/dim unrelated nodes
- Color gradient by distance from selected node
- Arrows showing data flow direction
- Toggle between upstream/downstream/both views
Dependency Panel
- Tree view of dependencies
- Expandable/collapsible hierarchy
- Click to select different node
- Copy dependency list
Acceptance Criteria
- Show upstream dependencies on node selection
- Show downstream dependents on node selection
- Visual highlighting with distance gradient
- Dependency tree in side panel
- Toggle between upstream/downstream/both
Technical Notes
- Use BFS/DFS from selected node
- Cache dependency trees (invalidate on topology change)
- Consider depth limit for very connected graphs