Initial commit: VMware vSphere API simulator scaffold.

Add the FastAPI app, PostgreSQL migrations, Docker/Helm packaging, API
contracts, docs, client examples, and the unit/integration/compatibility
test suite for local client and tooling labs without a real vCenter.

app/lifespan.py

@@ -0,0 +1,63 @@
+"""Application resource ownership."""
+
+from __future__ import annotations
+
+import asyncio
+from collections.abc import AsyncIterator, Callable
+from contextlib import AbstractAsyncContextManager, asynccontextmanager
+from typing import Protocol
+
+from fastapi import FastAPI
+
+from app.config import Settings
+from app.db.pool import AsyncpgDatabase, Database
+
+DatabaseFactory = Callable[[Settings], Database]
+Lifespan = Callable[[FastAPI], AbstractAsyncContextManager[None]]
+
+
+class LifespanWorker(Protocol):
+    async def run(self) -> None: ...
+
+    def stop(self) -> None: ...
+
+
+WorkerFactory = Callable[[Database], LifespanWorker]
+
+
+def create_lifespan(
+    settings: Settings,
+    database_factory: DatabaseFactory,
+    worker_factories: tuple[WorkerFactory, ...] = (),
+) -> Lifespan:
+    """Build a lifespan context so tests can inject a database implementation."""
+
+    @asynccontextmanager
+    async def lifespan(app: FastAPI) -> AsyncIterator[None]:
+        database = database_factory(settings)
+        await database.connect()
+        app.state.database = database
+        try:
+            from app.vsphere.seed import seed_vsphere_inventory
+
+            await seed_vsphere_inventory(database, force=False)
+        except Exception:
+            pass
+        workers = tuple(factory(database) for factory in worker_factories)
+        worker_tasks = tuple(asyncio.create_task(worker.run()) for worker in workers)
+        try:
+            yield
+        finally:
+            for worker in workers:
+                worker.stop()
+            if worker_tasks:
+                await asyncio.gather(*worker_tasks)
+            await database.close()
+
+    return lifespan
+
+
+def default_database_factory(settings: Settings) -> Database:
+    """Create the production asyncpg adapter."""
+
+    return AsyncpgDatabase(settings)