Implement KCA: web reimplementation of XCA PKI workflows

- kaya backend with OIDC sessions, API tokens, Postgres/Tortoise models
- AES-256-GCM private key storage and full certificate/CSR/CRL domain logic
- Sycamore/WASM SPA for vaults, keys, requests, certificates, CRLs and templates
- imports/exports, XCA .xdb migration, Docker Compose stack and tests

server/tests/helpers/asynctest.py

@@ -0,0 +1,23 @@
+"""``async_test`` that closes the app's per-loop Tortoise context."""
+from __future__ import annotations
+
+import asyncio
+from functools import wraps
+from typing import Any, Callable, Coroutine
+
+from kca.app import tortoise_mixin
+
+
+def async_test(coro: Callable[..., Coroutine[Any, Any, None]]) -> Callable[..., None]:
+    @wraps(coro)
+    def wrapper(*args: Any, **kwargs: Any) -> None:
+        async def run() -> None:
+            try:
+                await coro(*args, **kwargs)
+            finally:
+                await tortoise_mixin.aclose()
+
+        with asyncio.Runner() as runner:
+            runner.run(run())
+
+    return wrapper