Added direct graph navigation without activating Matplotlib toolbar modes:

Mouse wheel zooms in and out around the cursor.
Left-click dragging pans the graph.
Matplotlib toolbar modes still work and take precedence when activated.
The existing Home button can reset the view.

BEdit/AGENTS.md

@@ -151,6 +151,9 @@ Keep the root of `src/bedit` minimal. New UI modules should go into the relevant
   Signals tree checkboxes edit the active graph's traces, and each page embeds a
   Matplotlib QtAgg canvas. Each graph persists its own `x_axis` signal (default
   `time`), selectable from the Signals tree context menu.
+- Embedded Matplotlib canvases provide cursor-centered wheel zoom and direct
+  left-button drag panning without activating navigation-toolbar modes. Their
+  custom navigation toolbar restores an explicit data-derived home view.
 - Rerunning the same composed model retains graph tabs, ordering, titles, X axes,
   and surviving trace settings while replacing numeric data. Missing signals are
   pruned from traces/X-axis selection and newly returned columns appear in the tree.