kit: Add optional gpui-fast backend - #3375

## Summary
Enable GPUI Fast by default through `gpui-fast =
["gpui-kit/gpui-fast"]`. Update the native and web gallery dependencies
and simulate frame callbacks in three existing animation tests.

## Public API
`gpui-fast` Cargo feature: forwards backend selection to GPUI Kit;
enabled by default. Rust signatures are unchanged.

## Breaking Changes
The default backend changes from GPUI Pre to GPUI Fast.

## Dependencies
Uses GPUI Kit `main` after [PR
#3375](longbridge/gpui-kit#3375) merged. Do not
publish until the feature is released and the Git dependency is replaced
with the released version.

## Test plan
- [x] Default backend: 90 library tests and 25 gallery tests pass.
- [x] Without defaults: 90 library tests and all-target compilation
pass.
- [x] WASM gallery compiles on nightly.
- [x] Formatting and Clippy complete; Clippy reports three existing
warnings in surface/theme code.

AI-assisted with Codex.

Sync longbridge/gpui-kit upstream through 29c0457, including:
- kit: optional gpui-fast backend (longbridge#3375)
- webview: compose native views with the GPUI Fast backend (longbridge#3389)
- kit: one Windows manifest with GPUI Fast (longbridge#3380)
- input/diff/tooltip/test updates

Local fork kept: caret gpui-pre pins (navop resolves them via [patch] to
fork tags), IconColorMode color/mono extension, CE-generic ports.

## Description

On macOS with the default gpui-pre backend, the native `WKWebView` sits
above GPUI's Metal layer, so `PopupMenu`, dialogs and tooltips that
overlap the page are hidden behind it. Only GPUI Fast's window
composition places deferred overlays above the native view:

```text
front  GPUI overlay    deferred draws (PopupMenu, Dialog, Tooltip …)
       native surface  WKWebView / X11 child window
back   GPUI base       the root view
```

`gpui-webview` now always runs on GPUI Fast:

- It depends on `gpui-kit` with `default-features = false, features =
["gpui-fast"]` instead of on GPUI directly. Feature unification turns on
`gpui-fast` for the application's own `gpui-kit`, so **applications need
no manifest change**.
- The gpui-pre code paths and `#[cfg(feature = "gpui-fast")]` branches
are removed; composition is always used on macOS and Linux.
- The crate's `gpui-fast` feature is kept as a no-op so manifests that
enable it still resolve.
- `examples/webview` drops its `gpui-fast` feature; `cargo run -p
webview` shows the menu above the page.
- Because `gpui-webview` turns on `gpui-kit/gpui-fast` for every member
built with it, CI's workspace lint and test, and the `bump-gpui.ts` kit
check, exclude `gpui-webview` and `webview`; CI lints them in a separate
step and tests `gpui-webview` in the GPUI Fast job. The rest of the
workspace keeps checking gpui-pre.
- README and WebView docs (en / zh-CN) updated.

`cargo publish -p gpui-webview --dry-run` fails today because the
published `gpui-kit` 0.7.1 has no `gpui-fast` feature; it resolves once
the next `gpui-kit` release (which includes #3375) is published together
with this crate.

Verified on macOS: the example's "…" dropdown menu renders above the
WebView on GPUI Fast.

## Breaking Changes

No manifest change is needed, but an application that depends on
`gpui-webview` now runs entirely on GPUI Fast instead of gpui-pre.

## Public API

### `gpui-webview`

- `gpui-fast` feature — now has no effect; GPUI Fast is always used.
Kept for manifest compatibility.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

## Description

On macOS with the default gpui-pre backend, the native `WKWebView` sits
above GPUI's Metal layer, so `PopupMenu`, dialogs and tooltips that
overlap the page are hidden behind it. Only GPUI Fast's window
composition places deferred overlays above the native view:

```text
front  GPUI overlay    deferred draws (PopupMenu, Dialog, Tooltip …)
       native surface  WKWebView / X11 child window
back   GPUI base       the root view
```

`gpui-webview` now always runs on GPUI Fast:

- It depends on `gpui-kit` with `default-features = false, features =
["gpui-fast"]` instead of on GPUI directly. Feature unification turns on
`gpui-fast` for the application's own `gpui-kit`, so **applications need
no manifest change**.
- The gpui-pre code paths and `#[cfg(feature = "gpui-fast")]` branches
are removed; composition is always used on macOS and Linux.
- The crate's `gpui-fast` feature is kept as a no-op so manifests that
enable it still resolve.
- `examples/webview` drops its `gpui-fast` feature; `cargo run -p
webview` shows the menu above the page.
- Because `gpui-webview` turns on `gpui-kit/gpui-fast` for every member
built with it, CI's workspace lint and test, and the `bump-gpui.ts` kit
check, exclude `gpui-webview` and `webview`; CI lints them in a separate
step and tests `gpui-webview` in the GPUI Fast job. The rest of the
workspace keeps checking gpui-pre.
- README and WebView docs (en / zh-CN) updated.

`cargo publish -p gpui-webview --dry-run` fails today because the
published `gpui-kit` 0.7.1 has no `gpui-fast` feature; it resolves once
the next `gpui-kit` release (which includes longbridge#3375) is published together
with this crate.

Verified on macOS: the example's "…" dropdown menu renders above the
WebView on GPUI Fast.

## Breaking Changes

No manifest change is needed, but an application that depends on
`gpui-webview` now runs entirely on GPUI Fast instead of gpui-pre.

## Public API

### `gpui-webview`

- `gpui-fast` feature — now has no effect; GPUI Fast is always used.
Kept for manifest compatibility.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

## Description

Prepare v0.7.2 on `stable` from the PRs merged into `main` since v0.7.1,
leaving out every change that breaks existing consumers. `stable`
already carries #3371 and #3373; this adds the remaining compatible PRs
with `git cherry-pick -x` and bumps the workspace to 0.7.2.

### Included

- kit: Add optional gpui-fast backend (#3375)
- tooltip: Make show delay and grace period configurable with
`TooltipDefaults` (#3376)
- docs: Explain recovering focus when the focused element stops
rendering (#3386)
- diff: Add readonly patch viewer (#3378)
- kit: Use one Windows manifest with GPUI Fast (#3380)
- test: Make Progress and TitleBar findable in UI tests (#3383)
- input: Preserve selection, focus ring and context menu actions (#3382)
- diff: Add a Git history example and complete review APIs (#3388)
- text_view: Ignore gestures that stay inside one block plugin (#3390)
- text_view: Round the first and last table rows to the frame radius
(#3309)
- menu: Open a context menu with a long press on touch (#3393)
- text_view: Keep narrow table columns on one line (#3399)
- settings: Keep focus rings inside the list viewport (#3394)
- scrollable_mask: Keep rounded scroll-table corners clean at any scroll
offset (#3400)
- dialog: Add margin_top to AlertDialog (#3404)
- input: Add InputState::add_selection for programmatic multi-cursor
(#3403)
- text_selection: Stop writing selection state on every frame (#3407)
- table: Make the sort icon a labelled button (#3396)
- table: Report visible row ranges of one row or none (#3397)
- dialog: Support configurable entrance animations (#3405)
- docs: Explain the open_dialog builder and footer contracts (#3406)
- dock: Hand the focus to the tab that replaces a closed one (#3409)
- dropdown_button: Add A11y names for the menu trigger (#3410)
- text, resizable: Stop notifying state that did not change (#3418)
- editor: Add on-demand completion commands (#3411)
- table: Clear a right-clicked cell's outline on the next click (#3413)
- tab: Scroll a clicked tab into view with the next one peeking (#3419)
- table: Allow a header row height separate from the body (#3420)
- menu: Focus a context menu before its first frame (#3422)
- text: Preserve logical selection across presentation changes (#3421)
- text: Keep inline HTML mark highlights in Markdown (#3425)
- input: Anchor completion/code-action popups to the current frame's
caret (#3412)
- input: Run custom context menu builders after releasing the input
(#3433)
- input: Keep auto-grow rows fitted when the limits change (#3430)
- text: Paint TextView selection under the glyphs (#3439)

Already on `stable`: #3371, #3373.

### Excluded (Breaking Changes)

- #3432 motion: `Easing::sample` now returns values outside `[0, 1]` for
overshooting curves.
- #3415 tab: new `TabVariant::Folder` breaks exhaustive matches.
- #3402 kit: pointer helpers now keep held modifiers; nested
context-menu behavior changes in tests.
- #3384 test: `TestWindowExt` gains required methods.
- #3302 resizable: `ResizeHandle::on_drag` takes `&T` instead of
`Rc<T>`.
- #3389, #3395, #3398 webview: wrapper API changes, `gpui-wry` →
`gpui-webview` rename, and the GPUI Fast requirement.

#3411, #3405 and #3396 have a Breaking Changes section that reads "None"
and are included. #3376 only deprecates `TooltipRequest::placement`, and
#3397 / #3382 change behavior compatibly, so they are included too.

### Adaptations

- `crates/kit/tests/collections.rs` and `crates/kit/tests/rendering.rs`:
conflict resolutions drop the tests that belong to #3402 and keep each
backported PR's own test.
- `test: Keep backported tests on the v0.7.1 test API`: the menu and
completion tests from #3422 and #3412 used `find_all` and
`pointer_down`/`pointer_up` from #3384/#3402. They now query
`gpui_kit::base::test_support::snapshots` and dispatch mouse events
directly.
- `kit: Prepare v0.7.2`: workspace version bump; `Cargo.lock` only
updates workspace members.

## Public API

No new public API beyond what the included PRs add; each lists its items
in its own `## Public API` section (notably #3375, #3376, #3378, #3388,
#3403, #3404, #3405, #3411, #3420).

## How to Test

- `cargo clippy --workspace --all-targets -- --deny warnings` passes on
Linux.
- `cargo test -p gpui-kit --features "test-support component assets"
--test collections --test menu --test input` passes on Linux.
- The macOS-only `rendering` test (#3439 adds one case, the count is
updated to 11) was not run.

AI-assisted: the backport, conflict resolution and test adaptations were
done with Claude Code.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Floyd Wang <codelife721@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Gustave <gustavel@gmail.com>
Co-authored-by: luren <84951845+lurenjia534@users.noreply.github.com>
Co-authored-by: Ylin <ylinwind@gmail.com>
Co-authored-by: ihavecoke <mixboip@gmail.com>
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Co-authored-by: xxww0098 <shefkie1957@gmail.com>
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Co-authored-by: Sola <sola-ryu@users.noreply.github.com>
Co-authored-by: Andy Hsu <i@nn.ci>
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Co-authored-by: Henrik Øgård <henrik@ogard.no>
Co-authored-by: Henrik Øgård <henrikogaard@users.noreply.github.com>
Co-authored-by: Endless <endless@longbridge.com>
Co-authored-by: John Costa <costajohnt@gmail.com>
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