feat(runtime-api): serve settings schema labels in the client's ?locale=

GET /v1/settings/schema resolved every label, description and option label
through the Engine's own configured `locale`, falling back to LC_ALL /
LC_MESSAGES / LANG and then English. The desktop resolves its interface
language the same way but ends with the operating system's preferred
languages. A desktop opened from the Finder or the Dock has no LANG, so on a
Chinese macOS with `locale` unset the app drew Chinese chrome around English
Settings rows served by its own Engine child.

The route now takes an optional `?locale=<tag>`. A non-empty tag goes through
`resolve_locale`, so a shipped pack answers, per-key English fallback still
applies, and an unknown tag answers in English. With no tag, or an empty one,
the configured `locale` resolves as before. This is ops launch packet item 18
as recommended ("the desktop passes its UI locale"); codewhale-app sends it in
the matching commit. An older client sends nothing and sees no change.

Evidence:
- Live: target/debug/codewhale app-server --http with an empty HOME and no
  LANG. No query and ?locale=en -> "Compact at" / "Input history" / "Language";
  ?locale=zh-Hans -> 压缩阈值 / 输入历史 / 语言; ?locale=ja -> コンパクトしきい値 /
  入力履歴 / 言語; ?locale= and ?locale=xx-bogus -> English.
- cargo test -p codewhale-tui --lib settings_schema: 3 passed, 0 failed
  (15348 filtered out).
- npm test: node 413 pass / 7 skipped / 0 fail and 7/7, vitest 772/772 in
  74 files; npm run check:web: exit 0; cargo fmt --check: clean.
- CI-form clippy (--workspace --all-targets --all-features --locked, -D
  warnings with the CI allows): clean.

Refs CW-7406

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NBKbhx19BRbZtvWK8rVKjz

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- `GET /v1/settings/schema` accepts `?locale=<tag>` and resolves row labels,
+  descriptions and option labels in that locale, with the configured
+  `locale` as the default. The desktop sends the interface language it
+  shows, so a desktop opened from the Finder or the Dock on a Chinese
+  system, which has no `LANG`, no longer lists its Settings rows in English
+  under Chinese headings (Refs CW-7406).
 - `codewhale --continue` reopens a session whose terminal was closed or
   killed mid-turn. It used to print "Recovered interrupted session" and then
   exit with "session … is open in an interactive Codewhale session": the

crates/tui/src/runtime_api.rs

@@ -12093,7 +12093,8 @@ async fn set_config(
 /// This route projects it for HTTP clients — current values resolved from
 /// the owning store (settings.toml via [`crate::settings::Settings`],
 /// config.toml, or the notifications table), labels and descriptions
-/// resolved through the locale pack. Writes stay on `POST /v1/config`;
+/// resolved through the locale pack: the `?locale=` the client displays,
+/// else the configured `locale`. Writes stay on `POST /v1/config`;
 /// this route never invents a value, an option, or a validator.
 #[derive(Debug, Serialize)]
 struct SettingsSchemaResponse {
@@ -12210,8 +12211,14 @@ fn toml_value_at_path<'a>(document: &'a toml::Value, segments: &[&str]) -> Optio
     Some(current)
 }
 
+#[derive(Debug, Deserialize)]
+struct SettingsSchemaQuery {
+    locale: Option<String>,
+}
+
 async fn get_settings_schema(
     State(state): State<RuntimeApiState>,
+    Query(query): Query<SettingsSchemaQuery>,
 ) -> Result<Json<SettingsSchemaResponse>, ApiError> {
     use codewhale_config::notifications::NotificationSetting;
     use codewhale_config::settings_schema::{
@@ -12221,7 +12228,13 @@ async fn get_settings_schema(
 
     let config = state.config.read().clone();
     let settings = crate::settings::Settings::load_persisted().unwrap_or_default();
-    let locale = resolve_locale(&settings.locale);
+    let locale = resolve_locale(
+        query
+            .locale
+            .as_deref()
+            .filter(|tag| !tag.trim().is_empty())
+            .unwrap_or(&settings.locale),
+    );
     let notifications = config.notifications_config();
 
     // Conditional pairs share the TUI's rule: exactly one member is shown,