fix: improve activity rendering, spacing, and path truncation (#654)

* fix: polish activity tool rows and message spacing

Show each tool call as its own row in live and activity views
Keep tool descriptions inline with truncation and cleaner read-file paths
Tune spacing, todo counts, and bash timing display for clearer chat flow

* fix: refine activity tool rows and truncation behavior

Make activity collapse behavior consistent across modes and rename default mode label to Expanded
Show tool descriptions inline with improved spacing and one-row-per-tool rendering
Fix read/edit path truncation to clip from the start while keeping edit filenames highlighted

* fix: resolve chat activity lint regressions

Remove unused activity render mode state in message body
Mark path helper animation arg as intentionally unused to satisfy lint

packages/ui/src/components/sections/openchamber/OpenChamberVisualSettings.tsx

@@ -134,7 +134,7 @@ const ACTIVITY_RENDER_MODE_OPTIONS: Option<'collapsed' | 'summary'>[] = [
     },
     {
         id: 'summary',
-        label: 'Summary',
+        label: 'Expanded',
         description: 'Expand Activity by default.',
     },
 ];