Complete WP-0003 T06 pilot validation and sync credential routing docs

Close the dangling MVP pilots task with H1 provider-switch test, pilot
validation report, and resolver tenant-override fix. Add credential routing
guidance to AGENTS.md and Claude rules.

tests/test_sdk_wrapper.py

@@ -62,3 +62,16 @@ def test_safe_default_on_missing():
 
     assert client.get_boolean_value("no.such", False) is False
     assert client.get_string_value("no.such", "def") == "def"
+
+
+def test_h1_provider_switch_without_business_code_change():
+    """UC-H1: swap provider backends without changing evaluation call sites."""
+    client = FeatureControlClient()
+    context = {"tenant_id": "acme", "actor_type": "human"}
+
+    client.set_provider(LocalProvider({"tenant.preview": True}))
+    assert client.get_boolean_value("tenant.preview", False, context) is True
+
+    # Simulate migration to a different backend with the same OpenFeature contract
+    client.set_provider(LocalProvider({"tenant.preview": False}))
+    assert client.get_boolean_value("tenant.preview", True, context) is False