feat(translation-v2): final review — dual-engine translation row + DeepSeek polish override + dead code cleanup

OSGKeyboardExt/KeyboardViewController.swift

@@ -533,14 +533,28 @@ public final class KeyboardViewController: UIInputViewController {
             guard let self else { return }
             // v0.2.1: pick the polish mode once at task start so a
             // mid-flight toggle flip doesn't change the request we
-            // already sent. `isTranslationEffective` honours the cloud-
-            // only constraint so we never accidentally translate on the
-            // local engine.
+            // already sent. `isTranslationEffective` no longer gates on
+            // `engineMode == "cloud"` — the row visibility predicate
+            // already keeps the picker honest, and the local engine's
+            // translate-and-polish path now routes through DeepSeek.
             let polishMode: PolishingService.PolishMode = self.state.isTranslationEffective
                 ? .translate(targetLocaleId: self.state.translationTargetLocaleId)
                 : .polish
+            // v0.2.1: local engine routes through DeepSeek for the
+            // polish / translate step regardless of the user's chosen
+            // cloud provider — DeepSeek is cheap and strong on
+            // Chinese, which is the dominant input for the on-device
+            // ASR transcript. Cloud engine honors the user's own
+            // provider id by passing `nil`.
+            let overrideProviderId: String? = self.state.engineMode == "local"
+                ? "deepseek"
+                : nil
             do {
-                let polished = try await self.polisher.polish(trimmed, mode: polishMode)
+                let polished = try await self.polisher.polish(
+                    trimmed,
+                    mode: polishMode,
+                    providerIdOverride: overrideProviderId
+                )
                 self.textDocumentProxy.insertText(polished)
                 self.state.lastTranscript = ""
                 self.state.phase = .idle
@@ -588,19 +602,6 @@ public final class KeyboardViewController: UIInputViewController {
                     message: ExtL10n.string("keyboard.error.llm.noApiKey")
                 )
                 self.scheduleAutoClearError()
-            } catch let polishError as PolishingService.PolishError where polishError == .translationNotAvailable {
-                // v0.2.1: user toggled translation on while the local
-                // engine is active. Fall back to a plain polish — and if
-                // we're on local-without-cloud-polish, fall all the way
-                // back to raw ASR. The keyboard surfaces a short hint
-                // telling them to switch to the cloud engine.
-                self.textDocumentProxy.insertText(trimmed)
-                self.state.lastTranscript = ""
-                self.state.phase = .error(
-                    .unknown(ExtL10n.string("keyboard.error.translation.needsCloud")),
-                    message: ExtL10n.string("keyboard.error.translation.needsCloud")
-                )
-                self.scheduleAutoClearError()
             } catch {
                 // Network / timeout / decoding — fall back to the raw
                 // transcript so the user still gets their text, with a

OSGKeyboardExt/Views/TranslationChip.swift

@@ -12,12 +12,15 @@
 // derived from the locale id so the chip / pipeline read the same
 // source of truth.
 //
+// v0.2.1 final review: dropped the "needs cloud" warning state —
+// both engines now run the translate-and-polish step (the local
+// engine routes through DeepSeek via
+// `ProviderConfig.localModeProviderId`). The chip is therefore just
+// off / on, with the same accent treatment either way.
+//
 // Visual states:
 //   • off             → dim outline, "翻译" label
-//   • on + cloud      → accent fill, "→ EN" / "→ 日本語" style label
-//   • on + local engine→ warning fill + "翻译需云端" hint (effectively
-//     inert; the pipeline rejects the mode and the controller surfaces
-//     the error toast)
+//   • on (any engine) → accent fill, "→ EN" / "→ 日本語" style label
 //
 // Stays in the same visual family as `CloudEngineChip` / `LocaleChip`
 // (Capsule + 26 pt min height + 5 pt vertical padding) so the top bar
@@ -92,11 +95,10 @@ struct TranslationChip: View {
     }
 
     private func chipLabel(target: TranslationLanguage, enabled: Bool, isLocal: Bool) -> String {
-        // Local-engine + on shows the constraint hint instead of the
-        // target label so the user knows why nothing's happening.
-        if enabled, isLocal {
-            return ExtL10n.string("keyboard.translation.needsCloudShort")
-        }
+        // v0.2.1 follow-up: with the local engine now routing the
+        // polish / translate step through DeepSeek, the chip shows
+        // the same "→EN"-style label on both engines. There's no
+        // "needs cloud" hint path anymore.
         if !enabled {
             return ExtL10n.string("keyboard.translation.off")
         }
@@ -124,19 +126,23 @@ struct TranslationChip: View {
     }
 
     private func foreground(enabled: Bool, isLocal: Bool) -> Color {
-        if enabled, isLocal { return palette.warning }
+        // v0.2.1 follow-up: the chip no longer needs a "warning" path
+        // for local + on — both engines share the accent treatment
+        // now. `isLocal` is kept in the signature so callers don't
+        // need to change; it's intentionally unused below.
+        _ = isLocal
         if enabled { return palette.accent }
         return palette.textPrimary
     }
 
     private func background(enabled: Bool, isLocal: Bool) -> Color {
-        if enabled, isLocal { return palette.warning.opacity(0.15) }
+        _ = isLocal
         if enabled { return palette.accent.opacity(0.15) }
         return palette.surfaceElevated
     }
 
     private func stroke(enabled: Bool, isLocal: Bool) -> Color {
-        if enabled, isLocal { return palette.warning.opacity(0.35) }
+        _ = isLocal
         if enabled { return palette.accent.opacity(0.35) }
         return palette.divider
     }

OSGKeyboardExt/en.lproj/Keyboard.strings

@@ -181,10 +181,8 @@
 "keyboard.translation.off" = "Translate";
 "keyboard.translation.enable" = "Enable translation";
 "keyboard.translation.disable" = "Disable translation";
-"keyboard.translation.needsCloudShort" = "Need cloud";
 "keyboard.translation.a11y" = "Translation";
 "keyboard.translation.a11yHint" = "Toggle translation or change the target language.";
-"keyboard.error.translation.needsCloud" = "Translation needs the cloud engine — switch to cloud in Settings.";
 
 /* Mode chip labels (used in both ext + preview stub) */
 "mode.off" = "Off";

OSGKeyboardExt/zh-Hans.lproj/Keyboard.strings

@@ -181,10 +181,8 @@
 "keyboard.translation.off" = "翻译";
 "keyboard.translation.enable" = "开启翻译";
 "keyboard.translation.disable" = "关闭翻译";
-"keyboard.translation.needsCloudShort" = "需云端";
 "keyboard.translation.a11y" = "翻译";
 "keyboard.translation.a11yHint" = "切换翻译开关或修改目标语言。";
-"keyboard.error.translation.needsCloud" = "翻译需要云端引擎，请到设置切换为云端模式。";
 
 /* Mode chip labels */
 "mode.off" = "关闭";