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/db/migrations/003_durable_tasks.sql

@@ -0,0 +1,32 @@
+ALTER TABLE tasks
+    ADD COLUMN task_type text NOT NULL DEFAULT 'generic',
+    ADD COLUMN progress integer NOT NULL DEFAULT 0 CHECK (progress BETWEEN 0 AND 100),
+    ADD COLUMN result jsonb,
+    ADD COLUMN error text,
+    ADD COLUMN worker_id text,
+    ADD COLUMN lease_expires_at timestamptz,
+    ADD COLUMN cancel_requested boolean NOT NULL DEFAULT false,
+    ADD COLUMN idempotency_key text UNIQUE,
+    ADD COLUMN attempt integer NOT NULL DEFAULT 0,
+    ADD CONSTRAINT tasks_status_check CHECK (status IN ('queued', 'running', 'success', 'error', 'cancelled'));
+CREATE INDEX tasks_claim_idx ON tasks(status, lease_expires_at, created_at);
+CREATE TABLE resource_locks (
+    resource_key text PRIMARY KEY,
+    task_id uuid NOT NULL UNIQUE REFERENCES tasks(id) ON DELETE CASCADE,
+    acquired_at timestamptz NOT NULL DEFAULT now()
+);
+CREATE TABLE task_logs (
+    task_id uuid NOT NULL REFERENCES tasks(id) ON DELETE CASCADE,
+    sequence bigint GENERATED ALWAYS AS IDENTITY,
+    created_at timestamptz NOT NULL DEFAULT now(),
+    message text NOT NULL,
+    PRIMARY KEY (task_id, sequence)
+);
+CREATE TABLE task_events (
+    task_id uuid NOT NULL REFERENCES tasks(id) ON DELETE CASCADE,
+    sequence bigint GENERATED ALWAYS AS IDENTITY,
+    created_at timestamptz NOT NULL DEFAULT now(),
+    kind text NOT NULL,
+    data jsonb NOT NULL DEFAULT '{}'::jsonb,
+    PRIMARY KEY (task_id, sequence)
+);