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_deploy_workflow_env_input.py

@@ -40,35 +40,35 @@ def test_deploy_workflow_passes_env_flag_to_run_platform():
 
 def test_resolver_environment_override_changes_env():
     """D-088: environment_override changes the resolved environment."""
-    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]
     assert "qa" in s3["inputs"]["bucket_name"]
 
 
 def test_resolver_environment_override_prod():
-    stack = resolve(str(ROOT / "contracts" / "static-assets.yaml"),
+    stack = resolve(str(ROOT / "contracts" / "static-assets.yml"),
                     environment_override="prod")
     s3 = [r for r in stack["resources"] if r["type"] == "aws:s3:bucket"][0]
     assert "prod" in s3["inputs"]["bucket_name"]
 
 
 def test_resolver_environment_override_dr():
-    stack = resolve(str(ROOT / "contracts" / "static-assets.yaml"),
+    stack = resolve(str(ROOT / "contracts" / "static-assets.yml"),
                     environment_override="dr")
     s3 = [r for r in stack["resources"] if r["type"] == "aws:s3:bucket"][0]
     assert "dr" in s3["inputs"]["bucket_name"]
 
 
 def test_resolver_no_override_uses_contract_env():
-    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 "dev" in s3["inputs"]["bucket_name"]
 
 
 def test_resolver_override_none_uses_contract_env():
     """Passing environment_override=None uses the contract's environment."""
-    stack = resolve(str(ROOT / "contracts" / "static-assets.yaml"),
+    stack = resolve(str(ROOT / "contracts" / "static-assets.yml"),
                     environment_override=None)
     s3 = [r for r in stack["resources"] if r["type"] == "aws:s3:bucket"][0]
     assert "dev" in s3["inputs"]["bucket_name"]