chore: drop iOS 18–25 / non-iPhone support, require iOS 26

Two related cleanups the user asked for in one shot:

1. iPhone-only is now enforced at every target — Mac Catalyst and
   visionOS were never configured in `project.yml`, but the
   `OSGKeyboardShared` framework and the two test bundles were
   still defaulting to `TARGETED_DEVICE_FAMILY = "1,2"` (iPhone +
   iPad). All four targets now explicitly set `"1"`. SDK is
   `iphoneos` for everyone, no `xros` / `macosx`.

2. Deployment target bumped from iOS 18.0 to iOS 26.0 across the
   board (`project.yml` + the ext's per-target setting). With
   iOS 26 as the floor, the iOS 18–25 SFSpeechRecognizer path
   became dead code and several `#available` checks became
   always-true. Removed:

   - `AppleSpeechASR` (the entire SFSpeechRecognizer-based ASR
     backend) and the `#available(iOS 26.0, *)` factory branch.
     `ASRServiceFactory.make()` now returns `SpeechAnalyzerASR()`
     directly. SpeechAnalyzer is always fully on-device, which
     also made the `requiresOnDevice` flag meaningless.
   - `requiresOnDevice` from the `ASRService.transcribe` protocol
     signature, from `ProviderConfig`, `AppGroupStore`,
     `KeyboardState`, `AppGroupPersistor`, and the ext's
     `KeyboardViewController` (`state.requiresOnDevice`,
     `state.setRequiresOnDevice`, `persistRequiresOnDevice`).
   - `#available(iOS 17.0, *)` branch in
     `PreviewASRController.requestMicrophonePermission` and the
     ext's `PermissionManager.requestMicPermission` — both now
     just call the iOS 17+ `AVAudioApplication` API directly.
   - The `else` (iOS 18–25) branch in `SettingsView.asrEngineRow`
     — the on-device-only toggle is gone, the row is a static
     "SpeechAnalyzer active" badge. Same for the `else` branch
     in `EnginePickerSection.localSubtitle`.
   - `makeMicAuthHandler` (the iOS < 17 mic permission callback
     wrapper) from `PreviewASRController`.

   No `#available` / `@available` checks remain in the codebase
   except for the SpeechAnalyzer class itself (now unnecessary
   too, but kept for clarity — `AVAudioApplication` and
   `SpeechAnalyzer` are both iOS 17+ / iOS 26+ respectively,
   and the deployment target of 26 makes the explicit
   `@available` redundant; I left the SpeechAnalyzer class
   un-`@available` and removed the `@available(iOS 26.0, *)`
   decoration since it's no longer needed).

   The Keyboard ext's existing ASRService usage
   (`asr.transcribe(stream:locale:)`) is unchanged at the
   call-site level — just the third argument is gone.

3. Updated `info.plist` UISupportedInterfaceOrientations is
   already `[UIInterfaceOrientationPortrait]` only, which is
   correct for an iPhone-only app; no change needed.

Build: BUILD SUCCEEDED.
Tests: 22/22 pass.
Verified: `TARGETED_DEVICE_FAMILY = 1` on all four targets,
`SDKROOT = iphoneos` on all four.

🤖 Generated with Claude Code

OSGKeyboard/Views/SettingsView.swift

@@ -143,49 +143,31 @@ struct SettingsView: View {
         }
     }
 
-    /// ASR engine row — adapts to OS version:
-    /// • iOS 26+: shows a badge indicating SpeechAnalyzer is active (always on-device).
-    /// • iOS 18–25: shows a toggle to force on-device recognition only.
-    @ViewBuilder
+    /// ASR engine row. With iOS 26 as the deployment target, the
+    /// only ASR backend is `SpeechAnalyzer` and it is always fully
+    /// on-device — so this row is now a static badge rather than a
+    /// toggle. The previous `requiresOnDevice` toggle (iOS 18–25
+    /// `SFSpeechRecognizer` cloud-fallback control) is gone.
     private var asrEngineRow: some View {
-        if #available(iOS 26, *) {
-            HStack(spacing: Spacing.sm) {
-                Text("settings.engineRow.title")
-                    .font(TypeStyle.body)
-                    .foregroundStyle(palette.textPrimary)
-                Spacer()
-                HStack(spacing: 4) {
-                    Image(systemName: "iphone.badge.checkmark")
-                        .font(.system(size: 12, weight: .semibold))
-                        .foregroundStyle(palette.success)
-                    Text("settings.engineBadge.ios26")
-                        .font(TypeStyle.caption)
-                        .foregroundStyle(palette.success)
-                }
-                .padding(.horizontal, Spacing.xs)
-                .padding(.vertical, 4)
-                .background(palette.success.opacity(0.12), in: Capsule())
+        HStack(spacing: Spacing.sm) {
+            Text("settings.engineRow.title")
+                .font(TypeStyle.body)
+                .foregroundStyle(palette.textPrimary)
+            Spacer()
+            HStack(spacing: 4) {
+                Image(systemName: "iphone.badge.checkmark")
+                    .font(.system(size: 12, weight: .semibold))
+                    .foregroundStyle(palette.success)
+                Text("settings.engineBadge.ios26")
+                    .font(TypeStyle.caption)
+                    .foregroundStyle(palette.success)
             }
-            .padding(.horizontal, Spacing.md)
-            .padding(.vertical, Spacing.sm)
-        } else {
-            Toggle(isOn: Binding(
-                get: { config.requiresOnDevice },
-                set: { config.requiresOnDevice = $0 }
-            )) {
-                VStack(alignment: .leading, spacing: 2) {
-                    Text("settings.onDeviceOnly.title")
-                        .font(TypeStyle.body)
-                        .foregroundStyle(palette.textPrimary)
-                    Text("禁用云端回退，识别失败时会报错而非联网 · Disable cloud fallback, fail locally instead of going online")
-                        .font(TypeStyle.caption2)
-                        .foregroundStyle(palette.textTertiary)
-                }
-            }
-            .tint(palette.accent)
-            .padding(.horizontal, Spacing.md)
-            .padding(.vertical, Spacing.sm)
+            .padding(.horizontal, Spacing.xs)
+            .padding(.vertical, 4)
+            .background(palette.success.opacity(0.12), in: Capsule())
         }
+        .padding(.horizontal, Spacing.md)
+        .padding(.vertical, Spacing.sm)
     }
 
     /// Falls back to a static list while SFSpeechRecognizer locales are loading.