feat(P2): contract + stack-IR kyverno-json policies + resolver wiring (REQ-295..299)

contract/ policies (4): require-id-pattern, require-env-in-enum,
require-infrastructure-min-1, forbid-unknown-fields — declarative
mirrors of contract.schema.json constraints.

stack-ir/ policies (3): require-tagging-standard (nova:owner/contract/
environment/cost-center tags — ports nova_tagging.py), forbid-public-ingress
(v1.0 demo rule, now declarative), require-encryption-by-default (v1.8
D-encryption-default — S3 + EBS encryption config).

core/contract_resolver.py: pre-resolve contract-policy evaluation (REQ-296)
+ post-resolve stack-IR-policy evaluation (REQ-298). Additive — the resolver's
return shape + exceptions unchanged; PCRs attach to stack_instance.policyResults.
Policy evaluation never breaks the resolver (confidence signal decides gate).

tests: test_stack_ir_policies.py + passing/failing fixtures. Skip-without-kj.
16 existing resolver tests unchanged.

---ci---
project: acdl
phase: 2
milestone: v1.25
status: execute
phase_role: execution
requirements:
  covered: [REQ-295, REQ-296, REQ-297, REQ-298, REQ-299]
  partial: []
---/ci---

tests/fixtures/stack_ir/failing.json

@@ -0,0 +1,34 @@
+{
+  "version": "1.0.0",
+  "stack": {
+    "name": "bad",
+    "title": "failing stack",
+    "kind": "l1",
+    "depth": 1,
+    "environment": "dev"
+  },
+  "resources": [
+    {
+      "id": "bucket",
+      "type": "aws:s3:bucket",
+      "module": "s3@1.0.0",
+      "inputs": {
+        "bucket_name": "acdl-dev-bad-bucket",
+        "region": "us-east-1",
+        "tags": {
+          "nova:owner": "team-a"
+        }
+      }
+    },
+    {
+      "id": "service",
+      "type": "aws:ecs:service",
+      "module": "microservice@1.0.0",
+      "inputs": {
+        "image": "nginx:latest",
+        "port": 80,
+        "public_ingress": true
+      }
+    }
+  ]
+}

tests/fixtures/stack_ir/passing.json

@@ -0,0 +1,43 @@
+{
+  "version": "1.0.0",
+  "stack": {
+    "name": "msvc",
+    "title": "microservice",
+    "kind": "l1",
+    "depth": 1,
+    "environment": "dev"
+  },
+  "resources": [
+    {
+      "id": "bucket",
+      "type": "aws:s3:bucket",
+      "module": "s3@1.0.0",
+      "inputs": {
+        "bucket_name": "acdl-dev-msvc-bucket",
+        "region": "us-east-1",
+        "bucket_encryption": {"rule": {"apply_server_side_encryption_by_default": {"sse_algorithm": "AES256"}}},
+        "tags": {
+          "nova:owner": "team-a",
+          "nova:contract": "msvc",
+          "nova:environment": "dev",
+          "nova:cost-center": "cc-1"
+        }
+      }
+    },
+    {
+      "id": "service",
+      "type": "aws:ecs:service",
+      "module": "microservice@1.0.0",
+      "inputs": {
+        "image": "nginx:latest",
+        "port": 80,
+        "tags": {
+          "nova:owner": "team-a",
+          "nova:contract": "msvc",
+          "nova:environment": "dev",
+          "nova:cost-center": "cc-1"
+        }
+      }
+    }
+  ]
+}

tests/test_stack_ir_policies.py

@@ -0,0 +1,86 @@
+"""Tests for stack-IR kyverno-json policies (REQ-299, v1.25).
+
+Tests the 3 policies in adapters/kyverno-json/policies/stack-ir/:
+require-tagging-standard, forbid-public-ingress, require-encryption-by-
+default. Uses the passing + failing fixtures. Skips when kj is absent.
+"""
+
+import json
+import os
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import importlib.util
+_ENGINE_PATH = Path(__file__).resolve().parent.parent / "adapters" / "kyverno-json" / "kyverno_json_engine.py"
+_spec = importlib.util.spec_from_file_location("kyverno_json_engine", _ENGINE_PATH)
+_mod = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(_mod)
+KyvernoJsonEngine = _mod.KyvernoJsonEngine
+
+POLICY_DIR = Path(__file__).resolve().parent.parent / "adapters" / "kyverno-json" / "policies" / "stack-ir"
+FIXTURES = Path(__file__).resolve().parent / "fixtures" / "stack_ir"
+
+
+def _kj_installed() -> bool:
+    return _mod._which_kj() is not None
+
+
+@pytest.fixture(autouse=True)
+def _require_kj():
+    if not _kj_installed():
+        pytest.skip("kj not installed (scripts/install-kyverno-json.sh)")
+
+
+def _load(name):
+    with open(FIXTURES / name, "r", encoding="utf-8") as fh:
+        return json.load(fh)
+
+
+class TestPassingFixture:
+    def test_passing_fixture_all_pass(self):
+        eng = KyvernoJsonEngine()
+        out = eng.evaluate(_load("passing.json"), POLICY_DIR, "cid-pass")
+        assert isinstance(out, list)
+        assert len(out) >= 1
+        # No fail results on the passing fixture.
+        fails = [p for p in out if p["result"] == "fail"]
+        assert fails == [], f"expected no fails on passing fixture, got: {fails}"
+
+
+class TestFailingFixture:
+    def test_failing_fixture_has_fails(self):
+        eng = KyvernoJsonEngine()
+        out = eng.evaluate(_load("failing.json"), POLICY_DIR, "cid-fail")
+        fails = [p for p in out if p["result"] == "fail"]
+        assert len(fails) >= 1, "expected at least one fail on the failing fixture"
+
+
+class TestPolicyFilesExist:
+    def test_three_policies_present(self):
+        files = sorted(os.listdir(POLICY_DIR))
+        assert "require-tagging-standard.json" in files
+        assert "forbid-public-ingress.json" in files
+        assert "require-encryption-by-default.json" in files
+
+
+class TestPolicyValidity:
+    def test_policies_are_valid_json(self):
+        for f in os.listdir(POLICY_DIR):
+            if f.endswith(".json"):
+                with open(POLICY_DIR / f, "r", encoding="utf-8") as fh:
+                    data = json.load(fh)
+                assert data["apiVersion"] == "json.kyverno.io/v1alpha1"
+                assert data["kind"] == "ValidatingPolicy"
+                assert "nova.cloudinit.dev/severity" in data["metadata"]["annotations"]
+
+    def test_policy_names_match_filenames(self):
+        for f in os.listdir(POLICY_DIR):
+            if f.endswith(".json"):
+                with open(POLICY_DIR / f, "r", encoding="utf-8") as fh:
+                    data = json.load(fh)
+                expected = f.rsplit(".", 1)[0]
+                assert data["metadata"]["name"] == expected