i18n: an effect's name draws in the interface language, the generated Effect menu included (#821)

The interface below the menu bar is localized (618 fixed menu entries, ~490 panel rows) but an
effect's name still rendered in English everywhere it appeared: the generated Effect menu, Effect
Controls, the Timeline and Effects & Presets.

The registry's English name is the effect's identity: `effect.list`, `effect.apply {"effect": …}`,
scripts, expressions and the property tree's group name all match on it. Only the drawing changes.

`crates/ui-egui/src/i18n/effects.rs` keys the names by effect **id** rather than by the English
string — a repeat is stored as `Gaussian Blur 2` (an English key would miss it) and upstream
renames a display name now and then, while the id is stable. It carries 306 rows for Simplified
Chinese, one per effect in the registry, taken from the installed After Effects 2026 (26.5.0.89)
Simplified Chinese interface, with the `CC` series following Adobe's Chinese documentation (which
names 68 of the 69 that its interface leaves in English). `Cryptomatte`, `EXtractoR`, `IDentifier`,
`Key Light` and `Unmult` stay in English as brand names; `Face Measurements` and `Face Track
Points` are EffectCraft's own effects. The 21 category folder names are in the same file, worded
after the effect names (channel → 通道, noise → 杂色, matte → 遮罩 …).

What draws the catalog now:

- **Effect menu:** the entries and the category submenus. The command and its `{"effect": <id>}`
  params are untouched, so the menu still applies by id.
- **Effect Controls:** the header, its Rename field, the accessible name and the About popup.
- **Timeline:** effect group rows, and the search (a Chinese interface is searchable in Chinese).
- **Effects & Presets:** the rows, the drag ghost, the folder rows and the search.

Kept as they are: the effect id, the property tree's `PropGroup.name`, every automation id and
label, `effect.list`'s `name`/`category`, and the undo label (`Apply Gaussian Blur`). A name the
user typed in Effect Controls stays verbatim, and a repeated instance keeps the index the engine
appends (`Gaussian Blur 2` → `高斯模糊 2`). No other language has rows yet, Traditional Chinese
included, so those draw the registry's English name.

Tests: nine unit tests under `cargo test -p effectcraft-ui-egui --lib i18n` cover the data (every
effect has a row, the row still carries the registry's English name, ids are unique, only the five
brand names repeat their English name, every category has a row, a row names an effect the registry
knows) and the behaviour (the instance index, user renames, English and untranslated languages,
search) plus a scan pinning the drawing sites. `crates/ui-egui/tests/ui_effect_names.rs` checks the
Effect Controls header, the generated Effect menu and that the ids, automation labels and
`effect.list` stay English.

`docs/localization-parity.md` and `docs/gaps.md` no longer record effect names as deliberately
English; effect *parameter* names are still untranslated and stay the next piece.

Refs #821

docs/gaps.md

@@ -72,7 +72,7 @@ are grouped by area; the issue tracker has the rest.
 | 13 | **3D model formats and materials** | After Effects 26 imports FBX, USD/USDZ, STL besides glTF and OBJ (`usd_plugins`), and Substance 3D materials with mesh displacement (26.0–26.2); we read glTF, OBJ, STL (binary and ASCII, with facet colours) and FBX 7.x (binary and ASCII: meshes, hierarchy, Lambert/Phong materials and textures; no FBX animation or skinning yet) | Product shots and 3D scenes come as FBX/USDZ | 25–45 h | — · [file-format-parity.md](file-format-parity.md) |
 | 14 | **Object Matte** (26.2, disk cache in 26.5) | Not present; MobileSAM is already in `effectcraft-segment` and could back it | The new one-click roto; Roto Brush covers part of it | 15–30 h | G7 · [target-app-parity.md](target-app-parity.md) |
 | 15 | **Hardware video decode and encode** | No VideoToolbox, NVENC, Quick Sync or VA-API; #498 asks for it; FilmCraft has VideoToolbox / NVENC / VA-API paths to borrow | 4K playback and export speed | 25–45 h | G5/G6 · [hardware-parity.md](hardware-parity.md) |
-| 16 | **Localization depth** | Menus in 6 languages; panels in 4; effect names and ~1,650 effect parameter names untranslated; French, German, Korean, Italian, Russian (After Effects ships them) absent; #599 Hangul boxes on macOS | After Effects is used heavily in Japan, China, Korea, Brazil, Europe | 60–110 h + native review | G9 · [localization-parity.md](localization-parity.md) |
+| 16 | **Localization depth** | Menus in 6 languages; panels in 4; effect names translated in Simplified Chinese (306, plus the generated Effect menu), their ~1,650 parameter names untranslated; French, German, Korean, Italian, Russian (After Effects ships them) absent; #599 Hangul boxes on macOS | After Effects is used heavily in Japan, China, Korea, Brazil, Europe | 60–110 h + native review | G9 · [localization-parity.md](localization-parity.md) |
 | 17 | **Media Browser lists files import refuses** | `media_browser.rs` lists AVI; `media::is_importable` has none of them (Targa and Radiance HDR import since #745; DPX and Cineon since #756, log shown as stored: no Cineon Settings conversion yet; MXF OP1a / OP-Atom since #767; FilmCraft has no AVI demuxer); #431 any image imports as a sequence; #324 MP3 goes silent | Confusing failures on common VFX formats | 15–30 h | G6 · [file-format-parity.md](file-format-parity.md) |
 | 18 | **Relative paths and relinking** | Projects store absolute footage paths; no relink when a project moves | Moving or sharing a project breaks it | 6–12 h | G4 · [file-format-parity.md](file-format-parity.md) |
 | 19 | **Plug-in ecosystem** | No After Effects SDK hosting (#600, #327 OpenFX, #334, #376 plug-in manager); our WebAssembly API has no third-party plug-ins | Many pro projects depend on Trapcode, Element, Saber… | 40–80 h for API growth; SDK hosting needs an owner decision | G8 · [scripting-parity.md](scripting-parity.md) |