Generated App Tests: add th generate --with-tests scaffold

[snissn]

Background

• Tokenhost Builder now enforces builder-level CI (static, integration-local) and canonical job-board integration tests.
• Next step is generated-app-level testing so every app emitted by the generator includes runnable tests.

Scope

• Add th generate --with-tests (and define default behavior: on by default or explicit opt-in).
• Emit a tests workspace/package inside generated app output.
• Emit package scripts for generated apps (minimum: test, test:contract, test:ui placeholders when applicable).

Implementation details

• CLI/API:
  • th generate option surface and help text.
  • generated README in output describes how to run generated tests.
• Template wiring:
  • add reusable test template assets under packages/templates/next-export-ui (or adjacent package).
  • ensure generated app build still works when tests are included.

Acceptance criteria

• th generate <schema> --with-tests emits a deterministic tests directory.
• Generated app has runnable test commands without manual setup changes.
• Existing generator tests updated/expanded to assert emitted test scaffold.

[snissn]

Resolved in #33.\n\nImplemented:\n- scaffold emission\n- generated smoke scaffold files\n- generated app test scripts (, , ) when is used\n- CLI tests validating default-off and opt-in behavior

[snissn]

Resolution details (implemented in #33):

• Added th generate --with-tests scaffold emission.
• Generated app now includes ui/tests scaffold files:
  • tests/contract/smoke.mjs
  • tests/ui/smoke.mjs
  • tests/README.md
• When --with-tests is used, generated app package.json now includes:
  • test
  • test:contract
  • test:ui
• Added CLI tests validating default-off behavior and opt-in scaffold behavior.