Misc debug panel UX fixes

[pwang347]

Support resizing the tool call panel
Allow to select time stamps

Fixes #301259
Fixes #301261
Fixes #301263

[Copilot]

Pull request overview

This PR introduces several UX improvements to the chat debug panel:

• Adds number formatting (locale-aware) for token counts, durations, and other numeric values
• Replaces the fixed-width detail panel with a resizable sash-based panel
• Adds scrollable elements to detail panel and collapsible sections
• Adds a right-click context menu on debug events with copy and filter actions
• Enables JSON syntax highlighting for model turn sections
• Filters out 'unknown' status from display
• Removes auto-navigation to new sessions from the home view

Changes:

• Number formatting with safeIntl.NumberFormat() and .toLocaleString() across event detail renderers
• Resizable detail panel via Sash with DomScrollableElement for proper scrolling
• Context menu with copy/filter actions and refactored event text helpers

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
chatDebugEventDetailRenderer.ts	Added safeIntl.NumberFormat() for locale-aware number formatting
chatDebugEventList.ts	Extracted getEventCreatedText, getEventNameText, getEventDetailsText as exported helpers; added number formatting
chatDebugModelTurnContentRenderer.ts	Made renderModelTurnContent async with JSON syntax highlighting for sections; added toLocaleString() formatting; filters out 'unknown' status
chatDebugToolCallContentRenderer.ts	Exported tryParseJSON and renderSection for reuse
chatDebugDetailPanel.ts	Added resizable sash, DomScrollableElement, width tracking, and race-condition guard for async rendering
chatDebugLogsView.ts	Added context menu with copy/filter actions; relayout on detail panel width changes
chatDebugCollapsible.ts	Wrapped section content in DomScrollableElement
chatDebug.css	Added position: relative for sash anchoring; removed overflow-y: auto (now handled by scrollable elements); removed fixed width
chatDebugEditor.ts	Removed auto-navigation to new sessions
chatDebugEventDetailRenderer.test.ts	Adjusted test values below 1000 to avoid locale-dependent formatting issues

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