Generate conformance-test SAM templates from handler metadata

## Summary

PR #552 adds hand-maintained SAM templates for the Java conformance test suites. Each handler requires a largely repetitive Lambda resource plus a `TestingMetadata.TestDescription` mapping to conformance requirement IDs. As the number of handlers and suites grows, maintaining these mappings in both Java code and SAM YAML will be error-prone.

Add a script or build step that generates the conformance-test SAM templates from handler metadata.

Review context: https://github.com/aws/aws-durable-execution-sdk-java/pull/552#discussion_r3617917672

## Requirements

- Define one source of truth for the mapping between each Java handler and its conformance requirement IDs. This could be a Java annotation, a small manifest, or another explicit convention.
- Generate `template_.yaml` files deterministically for all conformance suites.
- Preserve the shared SAM configuration and each function's `TestingMetadata.TestDescription` values.
- Integrate generation into the local/CI conformance-test workflow so templates cannot silently drift from handlers or metadata.
- Document how to add a handler and its requirement mapping to an existing or new suite.

## Acceptance criteria

- Adding or removing a conformance handler requires no manual duplication of its Lambda resource in a SAM template.
- Generated templates pass SAM validation/build and run the existing step and wait conformance suites successfully.
- Generation is stable: running it twice without source changes produces no diff.
- CI fails when checked-in generated templates are stale, or generates templates before they are consumed if they are not checked in.

Commencez par la PR #552 et les modèles SAM de tests de conformité existants, maintenus manuellement, puis suivez les handlers Java et leurs correspondances TestingMetadata.TestDescription. Comparez le workflow local/CI des tests de conformité avec la validation/le build SAM ainsi qu’avec les suites step et wait. La tâche est terminée lorsque les modèles sont déterministes, que l’enregistrement des handlers est documenté, que les suites s’exécutent avec succès et que la CI protège contre les sorties générées obsolètes.

Rédigé par le modèle d'indexation à partir du texte de l'issue.