refactor(modules): remove thin-composition layer; rewrite all module READMEs

The L2 thin-composition layer (composition.json + contract_resolver.py +
contract schema + sample contracts) has been removed completely. The
implementation was unsatisfactory and is deferred for a later redesign.

- Delete: composition.json x2, contract_resolver.py, contracts/ x2,
  contract.schema.json
- Patch: run_platform.sh now loads a pre-existing IR instance instead of
  resolving a contract (the downstream adapter/checkov/confidence/outbox
  pipeline is unchanged)
- Prune: L2 entries removed from registry.json (L1 entries unchanged)
- Rewrite: all 7 L1 module READMEs in plain language (no jargon), each
  with Resources/Inputs/Outputs/Usage/Compliance-extension-points/Versioning
  sections derived from interface.json
- Add: 2 L2 placeholder READMEs noting the composition is under redesign
- Add: modules-ir/README.md catalog index + README-TEMPLATE.md

---ci---
project: acdl
phase: 17
milestone: v1.3
status: execute
---/ci---

contracts/microservice.yaml

@@ -1,13 +0,0 @@
-stack: l2-microservice
-environment: dev
-inputs:
-  name: acdl-microservice
-  cidr: "10.0.0.0/16"
-  azs: "us-east-1a,us-east-1b"
-  image: "581513795199.dkr.ecr.us-east-1.amazonaws.com/acdl-microservice:latest"
-  port: 8080
-  cpu: 256
-  memory: 512
-  role_name: acdl-microservice-exec
-  assume_role_policy: '{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":{"Service":"ecs-tasks.amazonaws.com"},"Action":"sts:AssumeRole"}]}'
-  managed_policies: "arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy"

contracts/spike.yaml

@@ -1,5 +0,0 @@
-stack: l2-static-asset
-environment: dev
-inputs:
-  bucket_name: acdl-spike-bucket
-  region: us-east-1