docs: update IMPLEMENTATION.md with v0.3.0 detailed plan and GitHub issue cross-references

[jcouball]

Summary

Updates IMPLEMENTATION.md to align with current open issues and provide a detailed roadmap for upcoming releases (v0.3.0, v0.4.0, v1.0.0).

Changes

v0.3.0 - Advanced Syntax and UX Enhancements

• Added Issue Prevent race conditions in mkdocs.yml file watcher callback #48 as Priority 0 - Race condition fix in mkdocs.yml watcher (quick win, 1-2 days)
• Expanded Issue UX: Improve preview visual differentiation and add per-snippet toggles #55 - UX improvements split into two phases:
  • Phase 1: Visual differentiation with [Preview] label, status bar indicator
  • Phase 2: Per-snippet toggles with CodeLens
• Added Issue Support multi-root workspaces for MkDocs config auto-detection #47 consideration - Multi-root workspace support as optional feature (with recommendation to defer to v0.4.0)
• Added comprehensive development tasks - 8-phase breakdown with weekly schedule
• Set realistic timeline - Q1 2026 (6-8 weeks estimated)

v0.4.0 - Performance and Robustness

• Reorganized features to prioritize security and performance:
  • Feature 1: Path traversal protection (Issue Security: Implement path traversal protection #52)
  • Feature 2: Symlink validation (Issue Security: Implement symlink validation and protection #54)
  • Feature 3: Performance and file size limits (Issue Performance: Implement file size limits and async loading #51)
  • Feature 4-8: Async loading, recursive processing, auto-refresh, error handling, state persistence
• Added detailed development tasks - 6-phase breakdown
• Set timeline - Q2 2026 (8-10 weeks estimated)
• GitHub issue cross-references throughout

v1.0.0 - Production Ready

• Added Issue Accessibility: Add screen reader support and keyboard navigation #53 - Accessibility features (screen reader support, keyboard navigation)
• Set timeline - Q3 2026 (6-8 weeks estimated)
• Updated success criteria to include accessibility requirements

Other Improvements

• Added GitHub issue links to all related features
• Removed duplicate development tasks sections (v0.4.0 had old tasks)
• Added effort estimates for individual features
• Improved section organization and clarity
• Added status tags (In Planning, Planned) to release headers

Rationale

This update ensures IMPLEMENTATION.md accurately reflects:

1. Current project status (v0.2.0 complete)
2. Open GitHub issues and their target releases
3. Clear priorities and dependencies
4. Realistic timelines based on complexity

The detailed breakdown helps with:

• Planning work for v0.3.0 (next release)
• Understanding dependencies between features
• Communicating project roadmap to contributors
• Tracking progress through phased tasks

Related Issues

• Addresses Prevent race conditions in mkdocs.yml file watcher callback #48, UX: Improve preview visual differentiation and add per-snippet toggles #55, Support multi-root workspaces for MkDocs config auto-detection #47, Performance: Implement file size limits and async loading #51, Security: Implement path traversal protection #52, Security: Implement symlink validation and protection #54, Accessibility: Add screen reader support and keyboard navigation #53

Checklist

• Updated IMPLEMENTATION.md with detailed v0.3.0 plan
• Added GitHub issue cross-references
• Set realistic timelines for v0.3.0, v0.4.0, v1.0.0
• Organized features by priority
• Added comprehensive development tasks breakdown
• Followed conventional commit format

[Copilot]

Pull request overview

This PR updates IMPLEMENTATION.md to provide a detailed roadmap for upcoming releases (v0.3.0, v0.4.0, v1.0.0) with GitHub issue cross-references, effort estimates, and comprehensive development task breakdowns.

Key Changes:

• Adds detailed v0.3.0 plan with 8-phase development schedule including a priority "quick win" race condition fix (Issue #48)
• Reorganizes v0.4.0 to prioritize security features (path traversal protection, symlink validation) ahead of other performance features
• Updates v1.0.0 to include accessibility requirements (Issue #53)