feat(scripts): add release branch management script

[monkey666-cr]

Summary

• Add bazel-jdt-bridge/scripts/create-release-branch.sh — a single-command tool that automates the release branch creation workflow defined in docs/release-guide.md
• Supports two modes: pre (pre-release, pre-release/tag-vX.Y.Z-pre.N) and stable (stable release, release/tag-vX.Y.Z)
• Auto-calculates next version from existing git tags using semver parsing
• Flags: --bump minor|major, --dry-run, --force, --push, --no-fetch

Usage Examples

# Next pre-release (v0.1.0-pre.1 → v0.1.0-pre.2)
./scripts/create-release-branch.sh pre

# Stable release (graduate v0.1.0-pre.N → v0.1.0)
./scripts/create-release-branch.sh stable

# Force minor version jump
./scripts/create-release-branch.sh pre --bump minor

# Preview without executing
./scripts/create-release-branch.sh pre --dry-run

Testing

All scenarios verified via --dry-run:

Command	Version Calculation	Result
pre	v0.1.0-pre.1 → v0.1.0-pre.2	✅
stable	v0.1.0-pre.1 → v0.1.0 (graduate)	✅
pre --bump minor	→ v0.2.0-pre.1	✅
stable --bump major	→ v1.0.0	✅
--dry-run	Print commands only	✅
Dirty working tree	Error exit	✅