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_local_emulating_adapters.py

@@ -181,7 +181,7 @@ def test_run_local_e2e_microservice():
     -> local ECS (HTTP 200) -> flat-file outbox -> local Lambda. No AWS."""
     os.environ["ACDL_LOCAL_TIER"] = "1"
     try:
-        result = le.run_local_e2e("contracts/microservice.yaml")
+        result = le.run_local_e2e("contracts/microservice.yml")
     finally:
         os.environ.pop("ACDL_LOCAL_TIER", None)
     assert result["tier"] == "local-emulator"
@@ -198,7 +198,7 @@ def test_run_local_e2e_static_assets():
     complete (ecs=None) and the outbox chain + Lambda stub must pass."""
     os.environ["ACDL_LOCAL_TIER"] = "1"
     try:
-        result = le.run_local_e2e("contracts/static-assets.yaml")
+        result = le.run_local_e2e("contracts/static-assets.yml")
     finally:
         os.environ.pop("ACDL_LOCAL_TIER", None)
     assert result["tier"] == "local-emulator"