Remove dead code from RunningActionState struct in executor.rs. The
execution_id, action_metadata, and started_at fields were stored but
never read. Only child_pid and output_buffer are actually used by the
stop() and get_buffered_output() methods.

This change eliminates unnecessary data storage and removes the
#[allow(dead_code)] attribute that was hiding the issue.

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Move all action items (run, build, format, check, test, cleanUp, prerun)
from the top-level "..." menu into an "Actions" submenu. This improves
organization and reduces visual clutter in the branch card menu.

Menu structure is now:
- Actions (submenu containing all project actions)
- Copy Worktree Path
- Delete

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Changed submenu overflow from 'hidden' to 'overflow-y: auto' with a
max-height of 400px to allow viewing all action items when the list
exceeds the viewport height. Previously, only the shadow was visible
when the submenu extended beyond the visible area.

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Fixed an issue where nested submenus (e.g., Build actions within the
Actions submenu) were not visible due to parent overflow clipping. The
fix ensures that only the first-level Actions submenu scrolls, while
nested submenus can overflow outside their parent container to remain
fully visible.

- Changed base .submenu from overflow-y: auto to no overflow
- Added specific rule for first-level submenus to enable scrolling
- Added rule for nested submenus to allow overflow: visible
- Added flex layout to submenu containers for proper sizing

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Remove nested category-based submenus (Run, Build, Format, etc.) from
the actions submenu to simplify the UI. All actions now display directly
in a single flat list within the Actions submenu.

Changes:
- Remove conditional logic that created nested submenus for 3+ actions
- Display all actions directly in the actions submenu
- Remove expandedSubmenu state and related submenu handlers
- Clean up CSS rules for nested submenus
- Simplify menu interaction logic

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>