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---

core/regression_verify.py

@@ -120,7 +120,7 @@ def _check_contract_schema_validation() -> Tuple[Status, str]:
         "import json, yaml, jsonschema; "
         "s=json.load(open('schemas/contract.schema.json')); "
         "[jsonschema.validate(yaml.safe_load(open(f)), s) "
-        " for f in ['contracts/static-assets.yaml','contracts/microservice.yaml']]; "
+        " for f in ['contracts/static-assets.yml','contracts/microservice.yml']]; "
         "print('2 sample contracts validate')",
     ])
 
@@ -144,7 +144,7 @@ def _check_resolver_static_assets() -> Tuple[Status, str]:
     try:
         return _check_subprocess([
             "python3", "core/contract_resolver.py",
-            "contracts/static-assets.yaml", out,
+            "contracts/static-assets.yml", out,
         ])
     finally:
         try:
@@ -160,7 +160,7 @@ def _check_resolver_microservice() -> Tuple[Status, str]:
     try:
         return _check_subprocess([
             "python3", "core/contract_resolver.py",
-            "contracts/microservice.yaml", out,
+            "contracts/microservice.yml", out,
         ])
     finally:
         try:
@@ -177,7 +177,7 @@ def _check_adapter_emits_terraform() -> Tuple[Status, str]:
     os.makedirs(tf_dir, exist_ok=True)
     rc, out, err = _run_subprocess([
         "python3", "core/contract_resolver.py",
-        "contracts/static-assets.yaml", stack_path,
+        "contracts/static-assets.yml", stack_path,
     ])
     if rc != 0:
         return "Broken", f"resolver failed: {err.strip()[-200:]}"
@@ -276,7 +276,7 @@ def _check_local_e2e_microservice() -> Tuple[Status, str]:
     This is the local-tier half of the headline E2E; the live-AWS half
     lands in Phase 54 (D-093)."""
     return _check_subprocess(
-        ["python3", "core/local_emulators.py", "contracts/microservice.yaml"],
+        ["python3", "core/local_emulators.py", "contracts/microservice.yml"],
         timeout=60,
     )
 
@@ -284,7 +284,7 @@ def _check_local_e2e_microservice() -> Tuple[Status, str]:
 def _check_local_e2e_static_assets() -> Tuple[Status, str]:
     """CAP-012: local E2E on the static-assets stack (no ECS service)."""
     return _check_subprocess(
-        ["python3", "core/local_emulators.py", "contracts/static-assets.yaml"],
+        ["python3", "core/local_emulators.py", "contracts/static-assets.yml"],
         timeout=60,
     )
 
@@ -324,7 +324,7 @@ def _check_live_terraform_plan_microservice() -> Tuple[Status, str]:
     os.makedirs(tf_dir, exist_ok=True)
     rc, out, err = _run_subprocess([
         "python3", "core/contract_resolver.py",
-        "contracts/microservice.yaml", stack_path,
+        "contracts/microservice.yml", stack_path,
     ])
     if rc != 0:
         return "Broken", f"resolver failed: {err.strip()[-200:]}"
@@ -364,7 +364,7 @@ def _check_live_terraform_plan_static_assets() -> Tuple[Status, str]:
     os.makedirs(tf_dir, exist_ok=True)
     rc, out, err = _run_subprocess([
         "python3", "core/contract_resolver.py",
-        "contracts/static-assets.yaml", stack_path,
+        "contracts/static-assets.yml", stack_path,
     ])
     if rc != 0:
         return "Broken", f"resolver failed: {err.strip()[-200:]}"