test: isolate shared-state test suites for CI stability

- add dependency injection to export-command, binary-manager,
  codex-plan-compatibility, config-command, and usage-syncer
- override process.exit in api-export test to prevent silent
  termination in Bun's parallel test runner
- harden test-environment bootstrap with process.env isolation
- fix auth middleware to avoid config upgrade during checks

tests/integration/image-analyzer-hook.test.ts

@@ -52,6 +52,7 @@ function invokeHook(env: Record<string, string> = {}): Promise<HookResult> {
     const child = spawn('node', [HOOK_PATH], {
       env: {
         ...process.env,
+        CCS_IMAGE_ANALYSIS_SKIP: '', // clear any inherited skip flag
         CCS_CLIPROXY_API_KEY: CLIPROXY_API_KEY,
         CCS_CLIPROXY_PORT: String(mockPort),
         CCS_IMAGE_ANALYSIS_ENABLED: '1',