test(cli): add zx TDD infrastructure and phase 1 tests

- Install zx as devDependency for E2E testing
- Create tests/ directory with setup utilities
- Add setup.ts with test context helpers:
  - Random port generation (never 6767)
  - Temp directory creation for PASEO_HOME and workDir
  - Daemon startup/waitForDaemon helper (WebSocket only)
  - Cleanup function
  - paseo() helper to run CLI commands against test daemon
- Add Phase 1 foundation tests (01-foundation.test.mts):
  - Test paseo --version outputs version
  - Test paseo --help shows commands
- Add test runner (run-all.mts) that discovers and runs all tests
- Add test:e2e script to package.json

packages/server/package.json

@@ -4,6 +4,7 @@
   "description": "Paseo backend server",
   "type": "module",
   "exports": {
+    ".": "./src/server/exports.ts",
     "./utils/tool-call-parsers": "./src/utils/tool-call-parsers.ts"
   },
   "scripts": {