feat: --target-revision | -r flag

[Q-Dub]

Add --target-revision flag for bootstrap script with git ancestry validation

Summary
This PR introduces a new --target-revision (-r) flag to the cluster-forge bootstrap script, allowing developers to bootstrap clusters from specific git revisions (branches, tags, or commits) while maintaining compatibility guarantees through git ancestry validation.
Problem Statement
Previously, the bootstrap script was hardcoded to use specific versions (v1.8.0-rc2), making it difficult for developers to:

• Test feature branches during development
• Bootstrap from specific releases or commits
• Validate cluster-forge changes before merging
  Additionally, there was a timing issue where ArgoCD applications would initially sync to the hardcoded revision before eventually switching to the intended target revision, causing unnecessary syncs.

Solution
🚀 Feature Implementation (commit 7dc274a)

• New CLI flag: -r/--target-revision with support for branches, tags, and commits
• Git ancestry validation: Ensures compatibility by checking that target revision is based on v1.8.0-rc1+
• Remote branch support: Handles both local branches and origin/branch-name patterns
• Simplified architecture: Removes pre-v1.8.0 compatibility complexity
• Enhanced error messages: Clear feedback for unsupported revisions
  🔧 Timing Fix (commit b5a0898)
• Immediate sync: ArgoCD applications now sync directly to specified revision from creation
• Architectural consistency: Maintains cluster-values repo override pattern
• Eliminates delay: No more initial sync to wrong revision followed by correction
  🧹 Template Cleanup (commit ded11b6)
• Remove v1.7.0 compatibility: Clean up conditional clusterSize logic
• Simplify template: global.clusterSize now always defined by bootstrap script
• Updated comments: Remove outdated backwards compatibility references

Usage Examples

• Bootstrap from a feature branch
  ./scripts/bootstrap.sh -r=EAI-1436_validation cluster.example.com
• Bootstrap from a specific tag
  ./scripts/bootstrap.sh --target-revision=v1.8.2 prod.example.com
• Bootstrap from main (default behavior)
  ./scripts/bootstrap.sh cluster.example.com
• Combined with cluster size
  ./scripts/bootstrap.sh -r=feature-branch -s=small dev.example.com

Validation & Safety

• ✅ Git ancestry checking: Only allows revisions based on v1.8.0-rc1 or later
• ✅ Remote branch detection: Automatically finds origin/branch-name if local branch missing
• ✅ Backwards compatibility: Existing usage patterns continue to work
• ✅ Clear error messages: Helpful guidance for unsupported revisions
• ✅ Syntax validation: All bash syntax checks pass

Impact
Benefits

• 🎯 Developer productivity: Easy testing of feature branches
• 🚀 Faster feedback: No wrong initial syncs
• 🧹 Cleaner codebase: Removed technical debt from v1.7.0 era
• 📋 Better UX: Clear validation and helpful error messages

Files Modified

• scripts/bootstrap.sh - Core feature implementation (+250/-131 lines)
• root/templates/cluster-forge.yaml - Template cleanup (-8/+1 lines)
• root/templates/_helpers.yaml - Minor comment fix (+1 line)
• scripts/init-gitea-job/values.yaml - Updated defaults (+12/-12 lines)

Testing
The feature has been tested with:

• ✅ Valid feature branches (e.g., EAI-1436_validation)
• ✅ Semantic version tags (e.g., v1.8.0, v1.8.2)
• ✅ Main branch (default behavior)
• ✅ Remote-only branches (origin/branch-name)
• ✅ Invalid pre-v1.8.0 revisions (properly rejected)

Breaking Changes: None. All existing bootstrap script usage continues to work as before.

[brownzebra]

lgtm!