refactor(P57): contract surface redesign + rename + .yml repo-wide

Contract surface redesign:
- New top-level fields: id (3-6 char acronym → stack.name), name (full → stack.title),
  infrastructure (map keyed by module name, replaces module:)
- Drop uses: field (dead reference; version pin lives in CI workflow uses: line)
- Drop top-level module/inputs (now nested under infrastructure map)
- Per-module optional version (defaults to latest published from registry)
- Multi-module contracts: one file deploys N modules in one pipeline run,
  resource IDs namespaced with module name to avoid collisions
- stack.schema.json: add optional title field for display name

Rename:
- pipelines/deploy.yaml → pipelines/contract.yml (declarative spec, not a pipeline)
- pipelines/ci.yaml → pipelines/ci.yml
- All 44 .yaml files → .yml repo-wide (contracts, module examples, kyverno policies)
- .acdl/contract.yaml → .acdl/contract.yml

Resolver (core/contract_resolver.py):
- Rewrite resolve() to loop infrastructure map, default version to latest,
  merge module fragments into one stack with namespaced resource IDs
- _latest_version() picks highest non-deprecated from registry
- _namespace_resources() prefixes IDs + rewrites ref: expressions for multi-module
- Single-module path: unprefixed IDs (backward compatible)

Verification:
- 494 tests pass (0 contract-shape failures)
- Local E2E passes (contract → resolver → adapter → local ECS HTTP 200 → outbox)

---ci---
project: acdl
phase: 57
milestone: v1.10.2
status: execute
---/ci---

tests/test_interpolation.py

@@ -24,21 +24,21 @@ def test_expand_env_dotted_path():
     assert _expand_vars("${env.state_backend.bucket}", ctx) == "acdl-dev-state"
 
 
-def test_expand_contract_module():
-    ctx = {"env": {}, "contract": {"module": "static-assets"}}
-    assert _expand_vars("${contract.module}", ctx) == "static-assets"
+def test_expand_contract_id():
+    ctx = {"env": {}, "contract": {"id": "assets"}}
+    assert _expand_vars("${contract.id}", ctx) == "assets"
 
 
 def test_expand_contract_dotted_path():
-    ctx = {"env": {}, "contract": {"inputs": {"bucket_name": "acdl-x"}}}
-    assert _expand_vars("${contract.inputs.bucket_name}", ctx) == "acdl-x"
+    ctx = {"env": {}, "contract": {"infrastructure": {"s3": {"inputs": {"bucket_name": "acdl-x"}}}}}
+    assert _expand_vars("${contract.infrastructure.s3.inputs.bucket_name}", ctx) == "acdl-x"
 
 
 def test_expand_nested_in_string():
     ctx = {"env": {"environment": "dev", "account_id": "000000000000", "region": "us-east-1"},
-           "contract": {"module": "static-assets"}}
-    result = _expand_vars("acdl-${env.environment}-${contract.module}-${env.account_id}-${env.region}", ctx)
-    assert result == "acdl-dev-static-assets-000000000000-us-east-1"
+           "contract": {"id": "assets"}}
+    result = _expand_vars("acdl-${env.environment}-${contract.id}-${env.account_id}-${env.region}", ctx)
+    assert result == "acdl-dev-assets-000000000000-us-east-1"
 
 
 def test_expand_recursive_in_dict():
@@ -81,24 +81,24 @@ def test_expand_non_string_passthrough():
 
 def test_resolve_static_assets_expands_bucket_name():
     """Resolving the sample contract produces the interpolated bucket name."""
-    stack = resolve(str(ROOT / "contracts" / "static-assets.yaml"))
+    stack = resolve(str(ROOT / "contracts" / "static-assets.yml"))
     s3 = [r for r in stack["resources"] if r["type"] == "aws:s3:bucket"][0]
-    assert s3["inputs"]["bucket_name"] == "acdl-dev-static-assets-000000000000-us-east-1"
+    assert s3["inputs"]["bucket_name"] == "acdl-dev-assets-000000000000-us-east-1"
     assert s3["inputs"]["region"] == "us-east-1"
 
 
 def test_resolve_microservice_expands_bucket_name():
-    stack = resolve(str(ROOT / "contracts" / "microservice.yaml"))
+    stack = resolve(str(ROOT / "contracts" / "microservice.yml"))
     # The microservice L2 wires bucket_name to vpc.inputs.cidr (legacy wire);
     # the interpolated value is a valid CIDR-like string. The key assertion
     # is that resolution succeeds with interpolation (no unresolved tokens).
-    assert stack["stack"]["name"] == "microservice"
+    assert stack["stack"]["name"] == "msvc"
 
 
 def test_resolve_with_environment_override_uses_overridden_env():
     """D-088: environment_override changes the interpolation context."""
-    stack = resolve(str(ROOT / "contracts" / "static-assets.yaml"),
+    stack = resolve(str(ROOT / "contracts" / "static-assets.yml"),
                     environment_override="qa")
     s3 = [r for r in stack["resources"] if r["type"] == "aws:s3:bucket"][0]
     # qa env: environment=qa, account_id=000000000000, region=us-east-1
-    assert s3["inputs"]["bucket_name"] == "acdl-qa-static-assets-000000000000-us-east-1"
+    assert s3["inputs"]["bucket_name"] == "acdl-qa-assets-000000000000-us-east-1"