fix(P26): generalize run_platform.sh check-only assertions for all contracts

The --check-only mode hardcoded static-assets-specific assertions
(stack name == 'static-assets', 'aws_s3_bucket' in main.tf, 'acdl-spike-bucket'
in main.tf). The platform-test.yml integration-test stage runs check-only for
every contracts/*.yaml, so contracts/microservice.yaml would fail the
AssertionError. Replace with generic structural checks valid for any contract.

verify(P0): code review — correctness

---ci---
phase: 26
milestone: v1.7
status: verify
lessons:
  - P0 fix applied: run_platform.sh check-only hardcoded static-assets assertions broke for non-static-assets contracts (microservice); generalized to structural checks
---/ci---

scripts/run_platform.sh

@@ -135,21 +135,19 @@ if [ "$CHECK_ONLY" = "1" ]; then
   python3 -c "
 import json, os
 d = json.load(open('$WORK/stack.json'))
-assert d['stack']['name'] == 'static-assets', f\"expected static-assets, got {d['stack']['name']}\"
-assert len(d['resources']) >= 1
+assert d['stack']['name'], 'stack name missing'
+assert len(d['resources']) >= 1, 'expected at least 1 resource'
 tf_dir = 'terraform/spike'
 for f in ('main.tf', 'terraform.tf', 'providers.tf'):
     assert os.path.isfile(os.path.join(tf_dir, f)), f'{f} missing'
 main = open(os.path.join(tf_dir, 'main.tf')).read()
-assert 'aws_s3_bucket' in main
-assert 'acdl-spike-bucket' in main
-assert 'versioning' in main
+assert len(main) > 0, 'main.tf is empty'
 tf = open(os.path.join(tf_dir, 'terraform.tf')).read()
 assert 'backend' in tf
 assert 'required_version' in tf
 prov = open(os.path.join(tf_dir, 'providers.tf')).read()
 assert 'provider \"aws\"' in prov
-print('adapter output: OK')
+print(f\"adapter output: OK ({d['stack']['name']}, {len(d['resources'])} resource(s))\")
 "
   echo ""
   echo "=== PLATFORM CHECK OK ==="