feat(cliproxy): add CLIProxyAPI integration for OAuth profiles

Complete integration of CLIProxyAPI for zero-config OAuth profiles.

New profiles:
- ccs gemini: Gemini via OAuth
- ccs chatgpt: ChatGPT via OAuth
- ccs qwen: Qwen via OAuth

Implementation:
- Phase 1: Binary infrastructure (download-on-demand)
- Phase 2: Proxy executor (spawn/kill pattern)
- Phase 3: OAuth integration (browser-based auth)
- Phase 4: Profile registration (routing + help text)
- Phase 5: Diagnostics (doctor command + errors)

Files added:
- src/cliproxy/*.ts (binary-manager, platform-detector, executor, auth-handler, config-generator, types, index)

Files modified:
- src/ccs.ts (CLIProxy routing)
- src/auth/profile-detector.ts (cliproxy profile type)
- src/commands/help-command.ts (new profiles in help)
- src/management/doctor.ts (CLIProxy health checks)
- src/utils/error-manager.ts (OAuth/port/download errors)
- CHANGELOG.md (v5.0.0 release notes)

Tests: 42/42 passed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@kaitranntt/ccs",
-  "version": "4.5.0",
+  "version": "5.0.0",
   "description": "Claude Code Switch - Instant profile switching between Claude Sonnet 4.5 and GLM 4.6",
   "keywords": [
     "cli",