pyproject.toml entrypoint for services; bytecode-first packing ships

Minor Changes

• 7bbfd48: Support "entrypoint": "pyproject.toml" for services. A service may now set entrypoint: "pyproject.toml" to build exactly what that file declares: the web app from tool.vercel.entrypoint (when present) and queue subscribers from [[tool.vercel.subscribers]]. Filename-based entrypoint auto-detection never runs in this mode, and subscribers-only services (no web function) are supported.

• f11c4c4: Bytecode-first packing for runtime-dependency-install builds (>225 MB) when VERCEL_PYTHON_COMPILEALL is enabled.

  The zip bundles only the mandatory packages plus a sys.pycache_prefix bytecode tree covering the app and all dependencies including those installed into /tmp at cold start, and defers every other public package to the cold-start uv sync. Falls back to knapsack packing (now with a slack-capacity bytecode fill) when the externalized set would not fit Lambda ephemeral storage.

Patch Changes

• 9637ae6: Add support for declaring the workflow entrypoint via tool.vercel.workflows in pyproject.toml.