Improve edit UI and priority colors

[Kombustor]

Summary

Improves task-editor clarity with consistent vector icons, colored priority flags, labelled icon-only controls, and cleaner energy labels across desktop and mobile. Adds a mobile close control wired through the existing unsaved-changes flow while preserving Save behavior and accessibility labels.

Related issue

Closes #1172

Testing

Full mobile & desktop test suite.

Screenshots / recordings

Checklist

• I have signed the Contributor License Agreement (CLA)
• I have tested this change locally
• I linked the relevant issue (or explained why there isn't one)
• I added or updated tests/docs if needed

[dongdongbh]

Ready to merge

Good work, this lands the whole of #1172 and the Priority quick action fits the other quick actions well, so it stays.

I pushed one commit on top of your branch (95fe85c) rather than asking for another round:

• The mobile editor header shows the word Save again. The X on the left is fine, but a first-time user needs to see which control commits the draft, so Save keeps its text. The header test now asserts that.
• The mobile widget now reads TASK_PRIORITY_COLORS from core and apps/mobile/lib/priority-colors.ts is gone, so there is one priority ramp for the app and the widget. The unused import in SwipeableTaskItemContent.tsx went with it.
• The lucide mock in apps/mobile/vitest.setup.ts now stubs any icon name instead of an allowlist. Navigation and about fifteen older imports were missing from the list, and the first test to render one of those fields would have failed far from the change.
• The last text glyphs on the lines you touched are lucide icons now: the sparkle on the desktop "Create project" option, the plus on the mobile Add item and picker create rows, and the check marks in the quick capture pickers.

[dongdongbh]

Ready to merge

Good work, this lands the whole of #1172 and the Priority quick action fits the other quick actions well, so it stays.

I pushed one commit on top of your branch (95fe85c) rather than asking for another round:

• The mobile editor header shows the word Save again. The X on the left is fine, but a first-time user needs to see which control commits the draft, so Save keeps its text. The header test now asserts that.
• The mobile widget now reads TASK_PRIORITY_COLORS from core and apps/mobile/lib/priority-colors.ts is gone, so there is one priority ramp for the app and the widget. The unused import in SwipeableTaskItemContent.tsx went with it.
• The lucide mock in apps/mobile/vitest.setup.ts now stubs any icon name instead of an allowlist. Navigation and about fifteen older imports were missing from the list, and the first test to render one of those fields would have failed far from the change.
• The last text glyphs on the lines you touched are lucide icons now: the sparkle on the desktop "Create project" option, the plus on the mobile Add item and picker create rows, and the check marks in the quick capture pickers.