hotfix(cliproxy): fallback from deleted CLIProxyAPIPlus to original backend

The upstream router-for-me/CLIProxyAPIPlus repo was deleted, breaking any
install/update path that resolved backend: plus. Existing users with
`backend: plus` saved in config.yaml hit 404s on every bootstrap.

Changes:
- Flip DEFAULT_BACKEND from 'plus' to 'original' (platform-detector.ts)
- Flip default cliproxy.backend in createEmptyUnifiedConfig() to 'original'
- Runtime 404 fallback: getConfiguredBackend() degrades 'plus' -> 'original'
  with a one-time warning, so existing installations keep working without a
  manual reconfig step
- Update CLIProxyBackend docblock to document the fallback behavior
- Update tests to match new default

Retains the 'plus' type and BACKEND_CONFIG entry for forward compatibility
once CCS self-maintains its own Plus fork.

Closes #1062

src/cliproxy/binary-manager.ts

@@ -32,15 +32,43 @@ import {
 import type { CLIProxyBackend } from './types';
 
 /**
- * Get backend from config or default to 'plus'
+ * Track whether we've already warned the user about the Plus fallback this
+ * process lifetime. Prevents spamming the warning on every command.
+ */
+let plusFallbackWarned = false;
+
+/**
+ * Get backend from config, with runtime fallback to 'original' when the user
+ * still has `backend: plus` saved.
+ *
+ * Context (issue #1062): the upstream `router-for-me/CLIProxyAPIPlus` repo was
+ * deleted, so any `backend: plus` install/update path hits a 404. Rather than
+ * forcing users to manually edit config.yaml, we degrade to `original` at
+ * runtime and warn once. This keeps existing installations working without a
+ * reconfig step, while CCS self-maintains its own Plus fork (future work).
  */
 function getConfiguredBackend(): CLIProxyBackend {
+  let configured: CLIProxyBackend;
   try {
     const config = loadOrCreateUnifiedConfig();
-    return config.cliproxy?.backend || DEFAULT_BACKEND;
+    configured = config.cliproxy?.backend || DEFAULT_BACKEND;
   } catch {
     return DEFAULT_BACKEND;
   }
+
+  if (configured === 'plus') {
+    if (!plusFallbackWarned) {
+      plusFallbackWarned = true;
+      warn(
+        'CLIProxyAPIPlus upstream repo is currently unavailable; falling back to ' +
+          '`backend: original`. Run `ccs config` to update your saved config. ' +
+          'Tracking: https://github.com/kaitranntt/ccs/issues/1062'
+      );
+    }
+    return 'original';
+  }
+
+  return configured;
 }
 
 /**
@@ -52,7 +80,7 @@ function getBackendBinDir(backend: CLIProxyBackend = DEFAULT_BACKEND): string {
   return `${baseDir}/${backend}`;
 }
 
-/** Default configuration (uses backend from config.yaml or defaults to 'plus') */
+/** Default configuration (uses backend from config.yaml or defaults to `DEFAULT_BACKEND`) */
 function createDefaultConfig(backend: CLIProxyBackend = DEFAULT_BACKEND): BinaryManagerConfig {
   const backendConfig = BACKEND_CONFIG[backend];
   return {

src/cliproxy/platform-detector.ts

@@ -29,8 +29,15 @@ export const BACKEND_CONFIG = {
   },
 } as const;
 
-/** Default backend */
-export const DEFAULT_BACKEND: CLIProxyBackend = 'plus';
+/**
+ * Default backend
+ *
+ * Set to 'original' because upstream `router-for-me/CLIProxyAPIPlus` was
+ * deleted (issue #1062). The original `router-for-me/CLIProxyAPI` repo is
+ * still maintained. Users with existing `backend: plus` configs are migrated
+ * at runtime via a 404 fallback in the installer (see binary/installer.ts).
+ */
+export const DEFAULT_BACKEND: CLIProxyBackend = 'original';
 
 /**
  * CLIProxyAPIPlus fallback version (used when GitHub API unavailable)

src/cliproxy/types.ts

@@ -148,8 +148,10 @@ export type CLIProxyProvider =
 
 /**
  * CLIProxy backend selection
- * - original: CLIProxyAPI (legacy provider subset)
- * - plus: CLIProxyAPIPlus (expanded provider support, default)
+ * - original: CLIProxyAPI (current default; upstream still maintained)
+ * - plus: CLIProxyAPIPlus (expanded provider support; upstream deleted as of
+ *   issue #1062 — runtime falls back to `original`. Retained for forward
+ *   compatibility once CCS self-maintains its own Plus build.)
  */
 export type CLIProxyBackend = 'original' | 'plus';
 

src/config/unified-config-types.ts

@@ -1016,7 +1016,7 @@ export function createEmptyUnifiedConfig(): UnifiedConfig {
     accounts: {},
     profiles: {},
     cliproxy: {
-      backend: 'plus',
+      backend: 'original',
       oauth_accounts: {},
       providers: [...CLIPROXY_SUPPORTED_PROVIDERS],
       variants: {},

tests/unit/cliproxy/backend-selection.test.js

@@ -28,8 +28,8 @@ describe('Backend Selection', () => {
   });
 
   describe('DEFAULT_BACKEND', () => {
-    it('defaults to plus backend for backward compatibility', () => {
-      assert.strictEqual(platformDetector.DEFAULT_BACKEND, 'plus');
+    it('defaults to original backend (Plus upstream deleted, issue #1062)', () => {
+      assert.strictEqual(platformDetector.DEFAULT_BACKEND, 'original');
     });
   });
 
@@ -45,9 +45,10 @@ describe('Backend Selection', () => {
       assert(info.binaryName.startsWith('CLIProxyAPIPlus_6.6.51-0_'));
     });
 
-    it('uses plus backend by default', () => {
+    it('uses original backend by default (Plus upstream deleted, issue #1062)', () => {
       const info = platformDetector.detectPlatform();
-      assert(info.binaryName.includes('CLIProxyAPIPlus'));
+      assert(info.binaryName.startsWith('CLIProxyAPI_'));
+      assert(!info.binaryName.includes('CLIProxyAPIPlus'));
     });
 
     it('uses fallback version when version not specified', () => {
@@ -76,9 +77,10 @@ describe('Backend Selection', () => {
       assert.strictEqual(name, expected);
     });
 
-    it('defaults to plus backend', () => {
+    it('defaults to original backend (Plus upstream deleted, issue #1062)', () => {
       const name = platformDetector.getExecutableName();
-      assert(name.includes('cli-proxy-api-plus'));
+      const expected = isWindows ? 'cli-proxy-api.exe' : 'cli-proxy-api';
+      assert.strictEqual(name, expected);
     });
   });
 
@@ -94,9 +96,10 @@ describe('Backend Selection', () => {
       assert(url.includes('router-for-me/CLIProxyAPIPlus/releases'));
     });
 
-    it('defaults to plus backend', () => {
+    it('defaults to original backend (Plus upstream deleted, issue #1062)', () => {
       const url = platformDetector.getDownloadUrl();
-      assert(url.includes('CLIProxyAPIPlus'));
+      assert(url.includes('router-for-me/CLIProxyAPI/releases'));
+      assert(!url.includes('CLIProxyAPIPlus'));
     });
   });
 

tests/unit/cliproxy/binary-manager-install.test.ts

@@ -78,7 +78,7 @@ describe('installCliproxyVersion', () => {
         skipAutoUpdate: true,
       })
     ).rejects.toThrow(
-      'CLIProxy Plus binary is not installed locally. Run "ccs cliproxy install" when you have network access.'
+      'CLIProxy binary is not installed locally. Run "ccs cliproxy install" when you have network access.'
     );
   });
 });