docs: Add Phase 1 implementation plan and project documentation

[ashleyshaw]

Summary

Add Phase 1 implementation plan and update project documentation for Release Process Redesign (Epic #1546). Comprehensive planning and specification files ready for Phase 1 critical fixes implementation.

Changes

• PHASE_1_IMPLEMENTATION_PLAN.md — Detailed step-by-step workflow for three critical fixes
• PROJECT_INDEX.md — Updated with all 47 child issues and GitHub issue references
• README.md — Updated status showing Phase 1 ready to start
• CHANGELOG.md — Entry for Release Process V2 specification

Related Issues

Resolves: #1546 (Epic: Release Process Redesign & Multi-Repo Support)

Changelog

Added

• Phase 1 implementation plan with step-by-step workflow
• Updated project documentation with all 47 child issues
• Updated status showing Phase 1 ready to start

Global DoD Checklist

• Changes follow coding standards
• Documentation is clear and complete
• All frontmatter properly formatted
• Links validated
• Ready for merge

[github-actions]

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