fix(tooltip): make tooltip popups click-through so they don't block underlying controls

[tellaho]

Category: fix
User Impact: Tooltips in the message composer (and across the app) no longer block clicks to the controls or text field underneath them.

Problem: Radix/shadcn TooltipContent renders a hoverable Portal popup positioned over the composer. When a button tooltip is visible, the popup sits on top of the message textarea and intercepts the mouse, so clicking into the field while the tooltip shows fails. Reported on the composer's formatting/action buttons.

Solution: Add pointer-events-none to the shared TooltipContent so the floating popup is click-through. This is applied at the shared-component level because every tooltip in the app shares the same overlap-eats-clicks behavior and none contain interactive content (audited 49 TooltipContent usages across 32 files — all purely informational labels; the interactive elements are all triggers, whose pointer events are untouched). The class is placed first in the string so a future interactive tooltip can override it via className through tailwind-merge.

This satisfies the WCAG content-on-hover-or-focus constraints: pointer-events-none only affects the floating popup, so trigger focus-to-show (screen-magnification accommodation) and the hover/show lifecycle are unchanged. Composer labels were checked for length — all succinct, none wrap.

File changes

desktop/src/shared/ui/tooltip.tsx
Prepend pointer-events-none to the shared TooltipContent class string so the tooltip Portal popup is click-through app-wide, while remaining overridable by a caller's className.

Reproduction Steps

1. Open a channel in the desktop app and bring up the message composer.
2. Hover (or focus) one of the composer's action buttons (Mention, Attach, Spoiler, Formatting) so its tooltip appears over the textarea.
3. Click on the textarea region covered by the tooltip — before this change the click was eaten; now the field receives the click and the tooltip is click-through.
4. Tab to a button to confirm focus still reveals the tooltip (focus-to-show preserved).

Screenshots/Demos

Click-through confirmed during review — tooltip renders over the textarea and the field shows through it: