[TheGreatAxios]

Adds ActionBar, the floating bottom action bar from Builder's document pane, so every product gets the same bar.

• Grouped actions with labels, icons, disabled, active and note states.
• Collapses to a handle; focus returns to the handle and back to the bar.
• Floating (sticky at the bottom of a scroll container) or inline row placement; overflow folds into a trigger.
• renderTrigger lets the host wrap the overflow trigger in its own Menu, so ActionBar stays in the root barrel without pulling in Menu.
• barRef points at the bar or handle.
• Stories for each state, including dark, popover and prepare.

Closes CL-11892

Verification

• bun run check: lint, format, typecheck, dep-guard, contrast and tests (855 pass).
• axe is clean on the stories.

[linear-code]

CL-11892

[TheGreatAxios]

Screenshots

Storybook, light theme unless noted.

collapsed

menu-open

row-overflow

disabled

focus

dark

popover

[corbits-triage]

Triage: Pass

No changes needed from you. A maintainer will review this pull request.

Notes:

• added code matches a code pattern: src/ui/action-bar.tsx:216 Nested ternary; use if statements or a lookup., src/ui/action-bar.tsx:218 Nested ternary; use if statements or a lookup., src/ui/action-bar.tsx:220 Nested ternary; use if statements or a lookup.

Triage will approve, label.