feat: comprehensive rewrite — push-to-talk pipeline, Typeless UI, Chinese

This is a major rewrite of OpenLessKeyboard, renamed to OSGKeyboard
and rebuilt end-to-end. 59 files changed (+3205/-1550).

Architecture
------------
- Rename project, targets, directories from OpenLess* to OSGKeyboard*
  (OpenLess / OpenLessKeyboard / OpenLessShared / OpenLessTests).
- AudioCaptureService rewritten as @unchecked Sendable class with
  OSAllocatedUnfairLock instead of an actor, so it survives Swift 6
  strict-concurrency checks while still serialising engine + converter
  state correctly.
- Single design system (Palette / Spacing / Radius / TypeStyle /
  Motion) lifted into OSGKeyboardShared so the host app and the
  keyboard extension stay in lock-step.

Push-to-talk — first-principles fix
-----------------------------------
- App Group + audio-input entitlements were stripped by Xcode's
  Automatic Signing. They are now declared in project.yml so
  'xcodegen generate' re-emits them every time. iOS Developer
  Account is untouched; only the App Group capability was added.
- State machine uses a real stored `phase` (was a derived shim
  that locked out every press after the first because
  recordStream was never nilled after the pipeline finished).
- Microphone permission is requested inside pressBegan (async
  Task) so the press flow optimistically enters .recording;
  permission denial surfaces a short error and returns to idle.
- Replaced LongPressGesture(0.15s) with a DragGesture +
  TapGesture pair separated by pressArmed, so a single tap no
  longer fires both onPressBegan and onTap simultaneously.
- Real RMS / peak level meter from the AVAudioEngine tap (was a
  pseudo-random walk); the visible waveform is now driven by
  actual audio.
- SFSpeechRecognizer(locale:) with selectable ASR locales
  (auto / zh-Hans / zh-Hant / en-US / ja-JP / ko-KR) for
  first-class Chinese / English / Japanese / Korean dictation,
  with on-device recognition when supported.
- AVAudioSession now deactivates on stop so other apps' audio
  routing is restored.

Keyboard UI — Typeless-inspired layout
---------------------------------------
- Hero area is 280 pt with a 96 pt record disc, breathing outer
  ring, and a 12-bar waveform driven by the real RMS.
- inputView.allowsSelfSizing + a heightAnchor constraint so iOS
  no longer crops the keyboard under the Spotlight bar / home
  indicator.
- Top bar: mode chip (Off / 转写 / 润色) + locale chip
  (Auto / 简体 / 繁體 / EN / 日 / 한) + status badge + ⚙.
- Bottom bar: globe / delete / 空格 / return — all 40 pt and
  balanced.
- RecordButton onPressEnded is now safe to fire from a quick
  press; pressArmed prevents double-firing.

LLM / Polishing
---------------
- LLMClient: stopped leaking the server response body in errors
  (server body is now logged at debug, never surfaced to UI);
  added a dedicated .rateLimited case for 429.
- PolishingService timeout 8s → 12s to accommodate slower
  domestic LLM providers.
- AppGroupStore.defaultSystemPrompt is now provider-aware
  (Chinese for zhipu/moonshot/qwen/deepseek, English otherwise).

Onboarding & Settings
---------------------
- Re-themed OnboardingView / HomeView / SettingsView on the
  new design system.
- ProviderPickerSection now shows 6 providers (OpenAI, DeepSeek,
  Qwen DashScope, 智谱 GLM, 月之暗面 Moonshot, Custom) with
  blurb + selected accent.
- PickerRow for Mode and ASR locale; System Prompt editor with
  reset-to-default.
- API settings page "Get an API key" used SwiftUI Link, which
  has a hit-test bug on iOS 18 that ate gestures from adjacent
  TextFields (manifested as "typing jumps to a website"). It is
  now an explicit Button + contentShape + .submitLabel(.done) on
  the fields.

Polish & tests
--------------
- LLMClientTests: 4 unit tests passing (ProviderConfig
  persistence + OpenAI request/response + HTTP error + missing
  key); test App Group renamed to the correct identifier.
- ProviderConfig.apply now captures the previous provider id
  *before* mutating, so switching providers actually resets the
  system prompt to the new default.

Build
-----
- Swift 6 strict concurrency, iOS 18.0 deployment target.
- Tested on Xcode 26 + iPhone 17 Pro simulator. A real device on
  iOS 27 beta aborts with __abort_with_payload (dispatch
  library ABI mismatch); use an iOS 18 real device or the
  iOS 26 simulator for now.

🤖 Generated with Claude Code

OSGKeyboardExt/Services/ASRService.swift

@@ -0,0 +1,151 @@
+// ASRService.swift
+// OSGKeyboard · Keyboard Extension
+//
+// Speech-to-text abstraction over Apple's `SFSpeechRecognizer`.
+// Honours a user-selected locale (auto / zh-CN / en-US / ja-JP …) so
+// dictation is first-class for non-English languages.
+
+import Foundation
+import AVFoundation
+import Speech
+import os.lock
+import OSGKeyboardShared
+
+// MARK: - Sendable conformance
+
+// `AVAudioPCMBuffer` and `SFSpeechRecognitionTask` are not Sendable. We
+// only ever access them serially — the PCM buffer is built and consumed
+// inside a single Task, and the recogniser task is cancelled but never
+// shared concurrently — so an unchecked conformance is sound here.
+extension AVAudioPCMBuffer: @unchecked @retroactive Sendable {}
+extension SFSpeechRecognitionTask: @unchecked @retroactive Sendable {}
+
+// MARK: - Protocol
+
+public protocol ASRService: Sendable {
+    /// Start a transcription session. The returned stream emits `.partial`
+    /// updates and exactly one `.final` (or `.error`) before finishing.
+    func transcribe(
+        stream: AsyncStream<AudioBufferSnapshot>,
+        locale: Locale
+    ) -> AsyncStream<ASREvent>
+
+    /// Cancel any in-flight recognition and tear down its tasks.
+    func cancel()
+}
+
+public enum ASREvent: Sendable, Equatable {
+    case partial(String)
+    case final(String)
+    case error(String)
+}
+
+// MARK: - Factory
+
+public enum ASRServiceFactory {
+    public static func make() -> ASRService {
+        AppleSpeechASR()
+    }
+}
+
+// MARK: - Apple Speech implementation
+
+final class AppleSpeechASR: ASRService, @unchecked Sendable {
+
+    private let lock = OSAllocatedUnfairLock()
+    private var recognizerTask: SFSpeechRecognitionTask?
+    private var feedTask: Task<Void, Never>?
+
+    func transcribe(
+        stream: AsyncStream<AudioBufferSnapshot>,
+        locale: Locale
+    ) -> AsyncStream<ASREvent> {
+        AsyncStream { continuation in
+            let recognizer = SFSpeechRecognizer(locale: locale)
+                ?? SFSpeechRecognizer(locale: .current)
+            guard let recognizer, recognizer.isAvailable else {
+                continuation.yield(.error("Speech recognizer unavailable for \(locale.identifier)"))
+                continuation.finish()
+                return
+            }
+            recognizer.defaultTaskHint = .dictation
+
+            let request = SFSpeechAudioBufferRecognitionRequest()
+            request.shouldReportPartialResults = true
+            request.requiresOnDeviceRecognition = recognizer.supportsOnDeviceRecognition
+
+            let task = recognizer.recognitionTask(with: request) { result, error in
+                if let error {
+                    let nsErr = error as NSError
+                    // Codes 203 / 1110 = "no speech detected" — a normal exit.
+                    if nsErr.code == 203 || nsErr.code == 1110 {
+                        continuation.yield(.final(""))
+                    } else {
+                        continuation.yield(.error(error.localizedDescription))
+                    }
+                    continuation.finish()
+                    return
+                }
+                guard let result else { return }
+                if result.isFinal {
+                    continuation.yield(.final(result.bestTranscription.formattedString))
+                    continuation.finish()
+                } else {
+                    continuation.yield(.partial(result.bestTranscription.formattedString))
+                }
+            }
+
+            self.lock.withLock { self.recognizerTask = task }
+
+            // Feed audio: for each snapshot, build a 16 kHz mono Float32
+            // PCM buffer and immediately `request.append(pcm)`. The PCM
+            // buffer never leaves this task, so it doesn't need to be
+            // Sendable.
+            let feedFormat = AVAudioFormat(
+                commonFormat: .pcmFormatFloat32,
+                sampleRate: 16_000,
+                channels: 1,
+                interleaved: false
+            )!
+            self.feedTask = Task { [request] in
+                for await snap in stream {
+                    if Task.isCancelled { break }
+                    guard !snap.samples.isEmpty,
+                          let pcm = AVAudioPCMBuffer(
+                            pcmFormat: feedFormat,
+                            frameCapacity: AVAudioFrameCount(snap.samples.count)
+                          )
+                    else { continue }
+                    pcm.frameLength = AVAudioFrameCount(snap.samples.count)
+                    if let dst = pcm.floatChannelData?[0] {
+                        snap.samples.withUnsafeBufferPointer { src in
+                            if let base = src.baseAddress {
+                                memcpy(dst, base, snap.samples.count * MemoryLayout<Float>.size)
+                            }
+                        }
+                    }
+                    request.append(pcm)
+                }
+                if !Task.isCancelled {
+                    request.endAudio()
+                }
+            }
+
+            continuation.onTermination = { @Sendable [weak self] _ in
+                self?.cancel()
+            }
+        }
+    }
+
+    func cancel() {
+        let (recTask, feedT) = lock.withLock { () -> (SFSpeechRecognitionTask?, Task<Void, Never>?) in
+            let r = self.recognizerTask
+            let f = self.feedTask
+            self.recognizerTask = nil
+            self.feedTask = nil
+            return (r, f)
+        }
+        recTask?.cancel()
+        feedT?.cancel()
+    }
+}