[eunomie]

Adds a script init template that generates a module as a single PEP 723 main.py instead of pyproject.toml + src/.

• main.py holds the # /// script block and the main object; sdk/ and clients/* stay beside it as path sources; the lock is main.py.lock.
• Layout is detected from files; no command converts an existing module.
• The build installs with uv sync --script --locked, keyed on the block, lock and path sources, so code edits keep the dependency layer.
• Refused in script mode: use-uv = false, the global client, migration from dagger.json.

Explain-changes: https://gistpreview.github.io/?41405c7a3ff4474a5aa5f9302093607e

Checks run (v1.0.0-beta.18 engine): helpers/pyproject Go tests, SDK pytest, ruff, and the e2e checks script-init, script-call, script-client, generate-scope-init, generate-scope-existing, find-client-root, runtime-call, entrypoint-client-call, shared-entrypoint-build, sdk-test.

Not run here: engine-e2e (floor-check, below-floor-check) and the remaining e2e checks; CI covers them.