feat(P27): add Examples section to every module README (D-058)

Each module README (10 primitives + 2 patterns) now has a ## Examples
section before ## Versioning, referencing and excerpting the validated
simple.yaml + complex.yaml (+ mysql.yaml for RDS) example contracts. The
RDS README includes a Multi-engine variation subsection (D-059).

---ci---
project: acdl
phase: 27
milestone: v1.7
status: execute
---/ci---

modules/l1/vpc/README.md

@@ -60,6 +60,44 @@ modules reference `subnet_ids` for their network placement.
 - **Security groups** — add `aws_security_group` as a first-class sub-resource (currently missing; needed for all regulated deployments) (SOC2 CC6.6, PCI-DSS 1.2).
 - **Network ACLs** — add `aws_network_acl` for subnet-level segmentation (PCI-DSS 1.3).
 
+## Examples
+
+Validated example contracts are in [`examples/`](examples/). The platform-test
+pipeline validates them against `schemas/contract.schema.json`.
+
+### Simple
+
+A minimal deployment:
+
+[`examples/simple.yaml`](examples/simple.yaml)
+```yaml
+uses: acdl/pipelines/deploy.yaml@v1.6
+module: vpc
+environment: dev
+inputs:
+  cidr: 10.0.0.0/16
+  azs: us-east-1a,us-east-1b
+  name: my-vpc
+  region: us-east-1
+```
+
+### Complex
+
+A production deployment with optional inputs:
+
+[`examples/complex.yaml`](examples/complex.yaml)
+```yaml
+# Complex VPC with 3 AZs and a custom CIDR
+uses: acdl/pipelines/deploy.yaml@v1.6
+module: vpc
+environment: dev
+inputs:
+  cidr: 10.50.0.0/16
+  azs: us-east-1a,us-east-1b,us-east-1c
+  name: my-production-vpc
+  region: us-east-1
+```
+
 ## Versioning
 
 `1.0.0` — interface MAJOR, behavior MINOR, lifecycle PATCH. MAJOR bumps