fix(cliproxy): add edge case handling for version capping

- Add isAboveMaxStable() helper for version stability checks
- Add null/empty guard in clampToMaxStable() function
- Warn users on unstable v81+ without forcing downgrade
- Add context note showing latest version when it's unstable
- Clamp fallback version on GitHub API failure

src/cliproxy/binary/lifecycle.ts

@@ -7,7 +7,7 @@ import * as fs from 'fs';
 import { BinaryManagerConfig } from '../types';
 import { checkForUpdates, fetchLatestVersion, isNewerVersion } from './version-checker';
 import { downloadAndInstall, deleteBinary, getBinaryPath } from './installer';
-import { info } from '../../utils/ui';
+import { info, warn } from '../../utils/ui';
 import { isCliproxyRunning } from '../stats-fetcher';
 import { CLIPROXY_DEFAULT_PORT } from '../config-generator';
 import { CLIPROXY_MAX_STABLE_VERSION } from '../platform-detector';
@@ -18,10 +18,22 @@ function log(message: string, verbose: boolean): void {
 }
 
 /**
- * Clamp version to max stable if newer versions are unstable
+ * Check if version is above max stable (known unstable)
  */
-function clampToMaxStable(version: string, verbose: boolean): string {
+function isAboveMaxStable(version: string): boolean {
-  if (isNewerVersion(version, CLIPROXY_MAX_STABLE_VERSION)) {
+  return isNewerVersion(version, CLIPROXY_MAX_STABLE_VERSION);
+}
+
+/**
+ * Clamp version to max stable if newer versions are unstable
+ * Returns max stable version if input is empty/invalid
+ */
+function clampToMaxStable(version: string | undefined, verbose: boolean): string {
+  if (!version) {
+    log(`Empty version, using max stable ${CLIPROXY_MAX_STABLE_VERSION}`, verbose);
+    return CLIPROXY_MAX_STABLE_VERSION;
+  }
+  if (isAboveMaxStable(version)) {
     log(`Clamping ${version} to max stable ${CLIPROXY_MAX_STABLE_VERSION}`, verbose);
     return CLIPROXY_MAX_STABLE_VERSION;
   }
@@ -31,17 +43,32 @@ function clampToMaxStable(version: string, verbose: boolean): string {
 /** Handle auto-update when binary exists */
 async function handleAutoUpdate(config: BinaryManagerConfig, verbose: boolean): Promise<void> {
   const updateResult = await checkForUpdates(config.binPath, config.version, verbose);
+  const currentVersion = updateResult.currentVersion;
+  const latestVersion = updateResult.latestVersion;
+
+  // Check if user is on known unstable version - inform but don't force downgrade
+  if (isAboveMaxStable(currentVersion)) {
+    console.log(
+      warn(
+        `CLIProxy Plus v${currentVersion} has known stability issues. ` +
+          `Stable version: v${CLIPROXY_MAX_STABLE_VERSION}`
+      )
+    );
+    console.log(info('Run "ccs cliproxy install 80" to downgrade, or wait for upstream fix'));
+  }
+
   if (!updateResult.hasUpdate) return;
 
   // Clamp to max stable version
-  const targetVersion = clampToMaxStable(updateResult.latestVersion, verbose);
+  const targetVersion = clampToMaxStable(latestVersion, verbose);
-  if (!isNewerVersion(targetVersion, updateResult.currentVersion)) {
+  if (!isNewerVersion(targetVersion, currentVersion)) {
-    log(`Already at max stable version ${updateResult.currentVersion}`, verbose);
+    log(`Already at max stable version ${currentVersion}`, verbose);
     return;
   }
 
   const proxyRunning = await isCliproxyRunning(CLIPROXY_DEFAULT_PORT);
-  const updateMsg = `CLIProxy Plus update available: v${updateResult.currentVersion} -> v${targetVersion}`;
+  const latestNote = isAboveMaxStable(latestVersion) ? ` (latest v${latestVersion} unstable)` : '';
+  const updateMsg = `CLIProxy Plus update: v${currentVersion} -> v${targetVersion}${latestNote}`;
 
   if (proxyRunning) {
     console.log(info(updateMsg));
@@ -95,7 +122,10 @@ export async function ensureBinary(config: BinaryManagerConfig): Promise<string>
         config.version = targetVersion;
       }
     } catch {
-      log(`Using pinned version: ${config.version}`, verbose);
+      // API failed - use fallback but still clamp to max stable
+      const fallbackVersion = clampToMaxStable(config.version, verbose);
+      config.version = fallbackVersion;
+      log(`Using fallback version: ${fallbackVersion}`, verbose);
     }
   } else {
     log(`Force version mode: using specified version ${config.version}`, verbose);