feat: 添加 Provider Registry、StatusLine、Cache Stats 和其他增强

- providerRegistry: OpenAI 兼容 provider 切换（Cerebras/Groq/DeepSeek/Qwen）
- StatusLine: 增强状态栏（缓存命中率、TTL 倒计时、自定义 shell 命令）
- cacheStats: 缓存命中率和 token 签名追踪
- ultrareviewPreflight: 代码审查预检服务
- SkillsMenu/filterSkills: 技能菜单过滤增强
- MagicDocs/langfuse prompts: 提示词更新
- claude.ts: API 客户端更新

Co-Authored-By: glm-5-turbo <zai-org@claude-code-best.win>

src/utils/cacheStatsState.ts

@@ -0,0 +1,92 @@
+/**
+ * In-memory singleton that tracks cache hit-rate state for the current session.
+ *
+ * Call `onResponse(usage)` every time a new API response arrives.
+ * The singleton compares the token signature of the new response against the
+ * previously seen signature.  When it changes (= a new API call completed),
+ * it resets `lastResetAt` to Date.now() and asynchronously persists state so
+ * that a future session can show the TTL countdown immediately on startup.
+ */
+
+import type { CacheUsage, CacheStatsState } from './cacheStats.js'
+import {
+  computeHitRate,
+  tokenSignature,
+  getStateFilePath,
+  readState,
+  writeStateAtomic,
+} from './cacheStats.js'
+
+interface MemState {
+  signature: string | null
+  lastResetAt: number | null
+  lastHitRate: number | null
+}
+
+let memState: MemState = {
+  signature: null,
+  lastResetAt: null,
+  lastHitRate: null,
+}
+
+let sessionId: string | null = null
+
+/**
+ * Must be called once at session start so the singleton knows which state file
+ * to persist to and can pre-load the last known state.
+ */
+export async function initCacheStatsState(sid: string): Promise<void> {
+  sessionId = sid
+  const filePath = getStateFilePath(sid)
+  const persisted = await readState(filePath)
+  // Pre-load persisted values so the UI can show fallback immediately
+  memState = {
+    signature: persisted.signature,
+    lastResetAt: persisted.lastResetAt,
+    lastHitRate: persisted.lastHitRate,
+  }
+}
+
+/**
+ * Called whenever a new assistant response is received with usage data.
+ * Returns the updated in-memory state.
+ */
+export function onResponse(usage: CacheUsage): MemState {
+  const sig = tokenSignature(usage)
+  const hitRate = computeHitRate(usage)
+
+  if (sig !== memState.signature) {
+    // New API response — reset the TTL clock
+    memState = {
+      signature: sig,
+      lastResetAt: Date.now(),
+      lastHitRate: hitRate,
+    }
+    // Persist asynchronously; intentionally fire-and-forget
+    if (sessionId !== null) {
+      const filePath = getStateFilePath(sessionId)
+      const toWrite: CacheStatsState = {
+        version: 1,
+        signature: sig,
+        lastResetAt: memState.lastResetAt,
+        lastHitRate: hitRate,
+      }
+      void writeStateAtomic(filePath, toWrite)
+    }
+  }
+
+  return { ...memState }
+}
+
+/** Read current in-memory state without triggering a response update. */
+export function getCacheStatsState(): MemState {
+  return { ...memState }
+}
+
+/**
+ * Reset singleton — used in tests to isolate test runs.
+ */
+export function _resetCacheStatsStateForTest(): void {
+  memState = { signature: null, lastResetAt: null, lastHitRate: null }
+  sessionId = null
+}