[dcoffin88]

Summary

Restores a compact, single-row compose toolbar by moving additional controls into an expandable More (+) menu, matching the existing mobile menu behavior.

Changes

• Moved AI Assist and HTML source editing into an expandable More menu on desktop.
• Right-aligned submenu icons on desktop so they appear directly beneath the cursor position when expanded.
• Added a code comment instructing future contributors to place additional toolbar buttons inside the expandable submenu to preserve the single-row layout.
• Unified toolbar behavior across desktop and mobile layouts.

Testing

Tested on my dev environment.

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[maathimself]

I tested this merged with current main, in Chromium, Firefox and WebKit. In main's default 540 px composer with AI on and a signature, AI and </> wrap to a second row; with this PR the toolbar stays on one row at 100% and 130% font size, and the + menu, AI Assist and </> all work. The + approach is fine. Two things before it can merge:

1. #577's tests. Merged with current main, 13 tests in ComposeModal.render.test.js fail: the Reply with AI and Write draft tests press the AI button directly, and it is now behind +. They need the same "press More first" step you added to aiApply and aiLength. Please merge main into the branch so CI runs them.
2. The table picker on a phone. This adds the table button to the phone toolbar, and openTable keeps the picker on screen by assuming it is 200 px wide. It is wider than that, so on a 360 px phone at 130% font size the 4×4 option runs off the right edge. Please clamp it with its real width, for example by measuring the picker once it renders, or by right-aligning it to the button when it would overflow.