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/007_realm_config.sql

@@ -0,0 +1,17 @@
+ALTER TABLE realms DROP CONSTRAINT IF EXISTS realms_kind_check;
+ALTER TABLE realms
+    ADD CONSTRAINT realms_kind_check
+    CHECK (kind IN ('pam', 'pve', 'openid', 'ldap', 'ad'));
+ALTER TABLE realms
+    ADD COLUMN IF NOT EXISTS config jsonb NOT NULL DEFAULT '{}'::jsonb;
+UPDATE realms
+SET config = config || jsonb_build_object(
+    'comment',
+    CASE name
+        WHEN 'pam' THEN 'Linux PAM standard authentication'
+        WHEN 'pve' THEN 'Proxmox VE authentication server'
+        ELSE COALESCE(config->>'comment', '')
+    END
+)
+WHERE name IN ('pam', 'pve')
+  AND COALESCE(config->>'comment', '') = '';