feat(FN-4036): fix zoom-aware graph pan bounds

Fixed zoom-aware graph pan bounds in the dependency graph plugin, correcting edge-case behavior when the graph is zoomed or panned. Added regression tests for graph interactions and updated documentation to cover the corrected behavior.

Fusion-Task-Id: FN-4036

plugins/fusion-plugin-dependency-graph/README.md

@@ -20,7 +20,8 @@ The dependency graph view is registered as a **bundled plugin view** in the dash
 - **Auto-layout**: Sugiyama-style layered layout (`computeAutoLayout`) groups nodes by dependency depth and spaces layers consistently
 - **Edge drawing**: SVG bezier curves from source bottom-center to target top-center, with arrowheads showing dependent → dependency direction
 - **Interaction**: drag-to-pan canvas background, drag-to-reposition nodes, cursor-centered wheel zoom, pinch-to-zoom with stationary midpoint, keyboard shortcuts, zoom toolbar, reset, and fit-to-graph
-- **Fit-to-graph**: computes node bounding box with layout node dimensions and applies zoom/pan so the graph fits in viewport with padding
+- **Zoomed navigation reachability**: pan clamping now scales with the full rendered graph bounds (min/max node extents) at the active zoom level, so zooming in no longer traps off-screen content behind fixed viewport-only limits
+- **Fit-to-graph**: computes node bounding box from both minimum and maximum node coordinates (including negative auto-layout origins) with layout node dimensions and applies zoom/pan so the graph fits in viewport with padding
 - **Initial auto-fit**: when no saved scoped positions exist, the first non-empty render auto-fits once; subsequent updates preserve user navigation state
 - **Position persistence**: dragged node positions are stored per project in browser localStorage and restored on reload
 - **Animated transitions**: fit/reset operations animate `transform` (`var(--transition-normal)`), while continuous drag/wheel/pinch stays transition-free for responsiveness