Merge branch 'sorted-insertion' of github.com:hazelgrove/hazel into sorted-insertion

Author: disconcision

plans/closure-cursor-bar.md

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+# Closure Cursor Bar
+
+## Status: Implemented, needs testing
+
+## What was done
+
+1. **Created `ClosureCursorBar.re`** - New component that displays call stack breadcrumbs
+   - Shows function names from applications in the call stack
+   - Uses arrow separators between entries
+   - Highlights the "focused" entry (at sample_cursor.index)
+   - Shows ghosted entries beyond current index
+   - Only appears when probes exist
+   - Shows "⌀" when at top level (empty call stack)
+   - Click on entry jumps to that syntax location
+
+2. **CSS in `style.css`** - Added closure cursor bar styling
+   - Positioned in row 2 of a 4-row grid layout
+   - Matches top bar aesthetics
+   - Hidden when no probes exist (via `.hidden` class)
+
+3. **Modified `Page.re`** - Integrated closure cursor bar into page layout
+   - Bar is rendered between top bar and main content
+
+4. **Modified `Transition.re`** - Added `RecordStackFrame` to built-in function applications
+   - Both print and other built-in functions now record stack frames
+
+5. **Fixed grid layout** - Added grid positioning to `#sidebars` in `style.css`
+
+## What needs testing
+
+- Closure cursor bar appearance when probes are active
+- Click-to-jump functionality
+- Breadcrumb display with nested function calls
+- Ghost indicator for entries beyond current index
+
+## Known limitations (documented in code)
+
+- Function names show "?" for applications inside built-in function implementations
+  (e.g., recursive calls within `map`) because those app_ids aren't in info_map
+- Future enhancement: Augment RecordStackFrame to carry function name directly
+
+## Files changed
+
+- `src/web/app/probesystem/ClosureCursorBar.re` (new)
+- `src/web/www/style.css`
+- `src/web/www/style/sidebar.css`
+- `src/web/app/Page.re`
+- `src/language/dynamics/transition/Transition.re`