bug: context note does not update when a tab in a split view is closed or a split pane is removed

[donivatamazondotcom]

Summary

In a split-view layout, closing a tab in one split pane or removing a split pane does not reliably refresh the context note badge. The badge continues to show the closed or no-longer-focused note instead of reflecting the new active state.

Possibly related to #265 (stale badge after closing last markdown note), but the mechanism may be distinct — this involves transitioning between focused panes rather than closing the last markdown file. Root cause not fully confirmed; filing as a separate issue so the repro is captured while investigation continues.

Repro scenarios

Multiple variants observed. All show the same stale-badge symptom.

Variant A: Split with two markdown tabs, close one.

1. Open the ACP chat panel.
2. Split the editor (e.g., Cmd+Shift+\ or drag a tab) so two markdown panes are visible side by side, each with its own markdown note.
3. Close the tab in one of the split panes (via tab ×, Cmd+W, or context menu).
4. Observe the context badge.

Expected: Badge updates to reflect the surviving pane's active note.

Actual: Badge may continue to show the closed pane's note, or stay on whichever note was focused prior to the close.

Variant B: Split pane is collapsed.

1. Set up a split with two markdown panes as above.
2. Close all tabs in one of the panes, causing that entire split pane to disappear.
3. Observe the context badge.

Expected: Badge reflects the remaining pane's active note.

Actual: Badge stays on the previous note from the removed pane.

Suspected mechanism

The active-leaf-change event behavior may differ when a leaf is destroyed (via pane/tab close) versus when focus moves between existing leaves. Possibilities under investigation:

• Event may fire with the wrong target leaf, or not fire at all on pane-collapse.
• The listener in attachToView may be invoked with the old view during the destroy phase, before the new active leaf is resolved.

I haven't yet confirmed whether the two-part fix proposed in #265 addresses these cases — I plan to test once the #265 fix is cherry-picked into a local build.

Next steps

1. Reproduce on the fix/context-note-stale-on-close branch to determine whether bug: context note does not update when the active note is closed (stays stale) #265's fix already covers these cases.
2. If covered, I'll add these as test cases / additional repros to the bug: context note does not update when the active note is closed (stays stale) #265 PR.
3. If not covered, I'll narrow the mechanism (likely an event-firing edge case on pane destroy) and propose a targeted fix.

Filing now so the symptoms are captured and discoverable.

Environment

• Obsidian 1.12.x
• Plugin version: latest dev (b57ab6c at time of report)
• Reproduced on macOS