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.

tests/unit/test_clock.py

@@ -0,0 +1,28 @@
+"""Simulation clock behavior."""
+
+import asyncio
+from datetime import UTC, datetime
+
+import pytest
+
+from app.simulation.clock import AcceleratedClock, ManualClock
+
+
+async def test_manual_clock_releases_sleep_only_after_advance() -> None:
+    clock = ManualClock(datetime(2026, 1, 1, tzinfo=UTC))
+    sleeper = asyncio.create_task(clock.sleep(10))
+    await asyncio.sleep(0)
+    assert not sleeper.done()
+
+    await clock.advance(9)
+    assert not sleeper.done()
+    await clock.advance(1)
+    await sleeper
+    assert await clock.now() == datetime(2026, 1, 1, 0, 0, 10, tzinfo=UTC)
+
+
+def test_clocks_reject_invalid_configuration() -> None:
+    with pytest.raises(ValueError):
+        AcceleratedClock(0)
+    with pytest.raises(ValueError):
+        ManualClock(datetime(2026, 1, 1))