Implement Vercel Build Cache Invalidation Strategy for Template Code Generation

[temma02]

Description

Implement a build cache invalidation strategy that ensures Vercel correctly rebuilds template deployments when the generated code changes, while preserving cache benefits when code is unchanged.

Requirements and Context

• Correctness: Stale builds must be invalidated when code changes
• Testing: Test cache invalidation on code change
• Documentation: Document the cache strategy

Suggested Execution

Branch: feat/issue-124-vercel-build-cache-invalidation

Implement Changes

• Compute a content hash of the generated template code
• Invalidate the Vercel build cache when the content hash changes
• Preserve the cache when the generated code is unchanged
• Surface cache hit/miss status in deployment logs

Test and Commit

• Test cache invalidation when generated code changes
• Test cache preservation when code is unchanged
• Document the cache strategy

Example Commit Message

feat(vercel): implement build cache invalidation for template code generation

- Compute content hash of generated code
- Invalidate cache on content hash change
- Preserve cache when code is unchanged

Guidelines

• Use a deterministic content hash
• Balance cache benefits against correctness
• Surface cache status in deployment logs