refactor(cliproxy): flatten module structure and colocate tests (#1135)

- Split types.ts (331 LOC) into 4 concern-based files under types/:
  platform-types, binary-types, provider-types, config-types
- Preserve backward compat via barrel re-export (types.ts → types/index)
- Reorganize 53 root-level files into 8 subdirectories:
  accounts/, ai-providers/, auth/, binary/, config/, executor/,
  management/, proxy/, quota/, routing/, services/, sync/
- Reduce src/cliproxy/ root from 65 to 8 files (target: ≤10)
- Colocate 87 unit tests from tests/unit/cliproxy/ into
  src/cliproxy/*/__tests__/ (13 colocated test directories)
- Update import paths across 40+ consumer files
- Add TDD backward-compat test for types split

Refs #1135

src/copilot/copilot-executor.ts

@@ -9,7 +9,7 @@ import { spawn } from 'child_process';
 import { CopilotConfig } from '../config/unified-config-types';
 import { getGlobalEnvConfig } from '../config/unified-config-loader';
 import { ensureCliproxyService } from '../cliproxy';
-import { getEffectiveApiKey } from '../cliproxy/auth-token-manager';
+import { getEffectiveApiKey } from '../cliproxy/auth/auth-token-manager';
 import { CLIPROXY_DEFAULT_PORT } from '../cliproxy/config/port-manager';
 import { checkAuthStatus, isCopilotApiInstalled } from './copilot-auth';
 import { isDaemonRunning, startDaemon } from './copilot-daemon';