Astrojarred/issue15

[astrojarred]

Closes #15.

We can now write SvelteKit server load functions in Python (+page.server.py and +layout.server.py)

• SvelteKit still runs load on the Node side, but the .py file gets turned into a thin JS shim that POSTs to a Python endpoint (/api/_load/...)
• No extra Python package for users to install — the runtime ships with the plugin and gets copied into the function bundle at build time.

Included:

• Return normal page/layout data from async def load(event)
• Use event.params, event.url, event.route, event.parent, event.data, event.cookies
• errors: return ("error", 404, "Not found")
• redirects: return ("redirect", 307, "/somewhere")
  Or call error(...) / redirect(...) with no import — they get injected when your module runs