fix(desktop): don't gate hover affordances on the hover media query (#3657)

## What problem this solves

Tailwind v4 compiles every `hover:` variant inside `@media (hover:
hover)`. Some
Windows hosts answer that query `false` **even with a mouse attached**,
and then
every hover-revealed control in the app is permanently `visibility:
hidden`.

Measured in the app's own WebView2 devtools console, on a mouse-driven
Windows 11
desktop:

```js
matchMedia('(hover: hover)').matches      // false
matchMedia('(any-hover: hover)').matches  // false
matchMedia('(pointer: fine)').matches     // false
matchMedia('(any-pointer: fine)').matches // false
navigator.maxTouchPoints                  // 10
```

Windows itself, on the same machine at the same moment, reports a mouse
present
and an integrated digitizer:

```
GetSystemMetrics(SM_DIGITIZER)      = 197   // INTEGRATED_TOUCH | INTEGRATED_PEN
                                            // | MULTI_INPUT | READY
GetSystemMetrics(SM_MAXIMUMTOUCHES) = 10
SystemInformation.MousePresent       = True
```

So this is not "the user has no mouse". Windows knows a mouse is
attached, and
Chromium still reports `any-pointer: fine: false` and `any-hover: false`
— the
`any-*` queries exist precisely to describe *any* available input
device, and
they are wrong here. The presence of an integrated touch digitizer
collapses the
reported capability to touch-only.

The compiled rule that never applies:

```css
.group-hover\/member\:visible {
  &:is(:where(.group\/member):hover *) {
    @media (hover: hover) { visibility: visible; }
  }
}
```

The row genuinely matches `:hover` (verified: `row.matches(':hover') ===
true`),
the button is in the DOM, the utility class is generated — and the
declaration
still never lands.

## Why this is more than one control

Not a single menu. Confirmed newly-ungated in the production bundle
after the
change:

| utility | media-gated before | after |
|---|---|---|
| `group-hover/member:visible` | yes | no |
| `group-hover/inbox-item:opacity-100` | yes | no |
| `group-hover/channel-row:opacity-100` | yes | no |
| `group-hover/attachment:opacity-100` | yes | no |
| `hover:bg-muted` | yes | no |

On an affected host the channel-member action menu (remove member,
change role,
start/stop agent) has **no reachable affordance at all**: `visibility:
hidden`
also removes the button from tab order, so there is no keyboard path
either.

## The fix

One line, at the root, next to the existing variant override:

```css
@custom-variant hover (&:hover);
```

This trusts the actual hover event rather than the capability query.
Chromium
only fires `:hover` when a real pointer is present, so behaviour on
hosts that
report the capability correctly is unchanged.

Verified against a production `vite build`, not just the dev server —
the
override cascades to the *named* group variants (`group-hover/member`,
etc.),
which is the part that matters here.

## Prior art in this repo

#2849 overrides Tailwind v4's `dark:` variant default at the *exact same
insertion point* in this file, for the same class of reason (a v4
default that
does not match how this app actually works). This change follows that
precedent.

**Note for whoever merges second: #2849 and this PR will conflict
textually** —
both append a `@custom-variant` immediately after `@config`. The
resolution is
to keep both lines; they are independent.

## Scope

Desktop only. `web/src/shared/styles/globals.css` has the same Tailwind
v4
default, but `web/src` contains **zero** `group-hover` usages, so there
are no
hover-revealed affordances to strand there. Adding the override to web
would be
speculative.

One `hover` capability query is deliberately left in place —
`.buzz-wave-hover-trigger` in `animations.css` gates a decorative
wave-hand
animation on `(hover: hover) and (pointer: fine)`. That is a cosmetic
flourish
rather than an affordance, so it stays inert on affected hosts instead
of
widening this diff.

## Reproducing

The trigger is **an integrated touch digitizer anywhere on the
machine**, not the
display you are actually working on. This was found on a touch-capable
laptop
docked to an ordinary non-touch external monitor, driven entirely by a
mouse — so
"I'm on a desktop monitor" does not rule you out. Check with:

```js
matchMedia('(hover: hover)').matches   // false ⇒ affected
```

Not reproducible on macOS, or on a Windows machine with no digitizer at
all —
`hover: hover` is true there and every affordance works normally. If you
are on
such a host, emulate it in devtools by forcing `hover: none` / `pointer:
coarse`,
then open a channel's member list and hover a row: no action menu
appears.

## Tradeoff worth naming

On a genuine touch-only device, a bare `&:hover` can latch after a tap
and stay
applied until the next interaction, where the media-query default would
have
suppressed it. That is the real cost of this change.

The judgement here is that a stuck hover style is a cosmetic annoyance,
while an
unreachable "remove member" button is a functional dead end — and that
the
affected hosts are overwhelmingly mouse-driven machines that merely
*happen* to
ship a digitizer, as the `MousePresent = True` reading above shows. If
you would
rather scope this to `@media not (hover: hover)` as an additive fallback
instead
of overriding the variant, I am happy to rework it.

Signed-off-by: sumit-m <33051892+sumit-m@users.noreply.github.com>

desktop/src/shared/styles/globals.css

@@ -1,5 +1,6 @@
 @import "tailwindcss";
 @import "tw-animate-css";
+
 @import "./globals/scrollbars.css";
 @import "./globals/motion.css";
 @import "./globals/animations.css";
@@ -17,3 +18,15 @@
 @import "./globals/progress.css";
 
 @config "../../../tailwind.config.js";
+
+/* Tailwind v4 gates `hover:` behind `@media (hover: hover)`. Some Windows
+   hosts answer that query `false` even with a mouse attached — WebView2 here
+   reports `hover: none`, `any-pointer: fine: false`, `maxTouchPoints: 10` —
+   which leaves every hover-revealed control permanently `visibility: hidden`:
+   member row action menus, sidebar row actions, attachment controls. A bare
+   `&:hover` trusts the actual hover event instead of the capability query;
+   Chromium only fires :hover when a real pointer is present.
+
+   Must stay below every `@import`: CSS requires `@import` to precede other
+   at-rules, so placing this above them silently drops the rest of the sheet. */
+@custom-variant hover (&:hover);