chore: prepare v0.20.0 LTS release

- Update version to 0.20.0 in pyproject.toml, setup.py, and all __init__.py files
- Add comprehensive v0.20.0 LTS release notes to CHANGELOG.md
- Add LTS designation to README.md
- Update migration guide to v0.20.0 LTS
- Mark v0.20.0 as Long-Term Stable release

This release marks the stabilization of SpecFact CLI's core analysis and
enforcement capabilities, positioning the tool for public promotion and
early adopter usage.

Author: djm81

CHANGELOG.md

@@ -9,6 +9,51 @@ All notable changes to this project will be documented in this file.
 
 ---
 
+## [0.20.0] - 2025-12-17
+
+### 🎉 Long-Term Stable (LTS) Release
+
+**v0.20.0 is the Long-Term Stable (LTS) release for the 0.x series.** This release marks the stabilization of SpecFact CLI's core analysis and enforcement capabilities, positioning the tool for public promotion and early adopter usage.
+
+**0.x Positioning**: "Analyze your brownfield code, find gaps, enforce contracts"  
+**1.x Positioning**: "All of the above, PLUS AI-assisted code generation with validation"
+
+### Added (0.20.0)
+
+- **LTS Designation**: v0.20.0 marked as Long-Term Stable release
+- **Comprehensive Documentation**: Complete GitHub Pages integration with navigation and styling
+- **Migration Guide**: Updated migration guide from v0.16.x to v0.20.0 LTS
+
+### Improved (0.20.0)
+
+- **Documentation Site**: Enhanced Jekyll-based documentation with left-side navigation
+- **Code Block Styling**: Fixed syntax highlighting for better readability
+- **User Experience**: Improved documentation navigation and accessibility
+
+### Breaking Changes (0.20.0)
+
+**None** - v0.20.0 is fully backward compatible with v0.19.0.
+
+### Deprecated (0.20.0)
+
+- `implement tasks` command remains deprecated (removed in v1.0)
+- Use `generate fix-prompt` and `generate test-prompt` bridge commands instead
+
+### Docs (0.20.0)
+
+- **GitHub Pages**: Complete Jekyll integration with proper rendering
+- **Navigation**: Left-side navigation sidebar for better UX
+- **Styling**: Fixed CSS issues and improved code block readability
+- **Migration Guide**: Updated guide for v0.16.x → v0.20.0 LTS upgrade path
+
+### Notes (0.20.0)
+
+- **LTS Support**: v0.20.0 will receive bug fixes and security updates until v1.0 GA
+- **Next Steps**: v1.0 development begins after Phase B validation (Ultimate Vision track)
+- **Stability**: All core features (analysis, enforcement, gap detection) are stable and production-ready
+
+---
+
 ## [0.19.0] - 2025-12-17
 
 ### Added (0.19.0)

README.md

@@ -16,9 +16,11 @@
 
 ---
 
-## 📋 Current Version: 0.17.x (Analysis & Enforcement)
+## 📋 Current Version: 0.20.0 LTS (Long-Term Stable)
 
-**SpecFact 0.x focuses on what it does best: analyzing legacy code and enforcing contracts.**
+**🎉 v0.20.0 is the Long-Term Stable (LTS) release!** This version marks the stabilization of SpecFact CLI's core analysis and enforcement capabilities.
+
+**SpecFact 0.20.0 LTS focuses on what it does best: analyzing legacy code and enforcing contracts.** This LTS release is production-ready and will receive bug fixes and security updates until v1.0 GA.
 
 | Capability | Status | Description |
 |------------|--------|-------------|

docs/guides/migration-0.16-to-0.19.md

@@ -1,10 +1,10 @@
-# Migration Guide: v0.16.x to v0.19.x
+# Migration Guide: v0.16.x to v0.20.0 LTS
 
-This guide helps you upgrade from SpecFact CLI v0.16.x to v0.19.x.
+This guide helps you upgrade from SpecFact CLI v0.16.x to v0.20.0 LTS (Long-Term Stable).
 
 ## Overview
 
-v0.17.0 - v0.19.0 are part of the **0.x stabilization track** leading to v0.20.0 LTS.
+v0.17.0 - v0.20.0 are part of the **0.x stabilization track** leading to v0.20.0 LTS.
 
 ### Key Changes
 
@@ -13,6 +13,7 @@ v0.17.0 - v0.19.0 are part of the **0.x stabilization track** leading to v0.20.0
 | **0.17.0** | Deprecated `implement` command, added bridge commands, version management |
 | **0.18.0** | Updated documentation positioning, AI IDE bridge workflow |
 | **0.19.0** | Full test coverage for Phase 7, migration guide |
+| **0.20.0 LTS** | Long-Term Stable release - production-ready analysis and enforcement |
 
 ---
 
@@ -154,7 +155,7 @@ Add version check to your GitHub Actions:
 
 ### Q: Can I still use v0.16.x?
 
-**A:** Yes, v0.16.x will continue to work. However, we recommend upgrading to v0.19.x for the latest fixes and features. v0.20.0 will be the Long-Term Stable (LTS) release.
+**A:** Yes, v0.16.x will continue to work. However, we recommend upgrading to v0.20.0 LTS for the latest fixes, features, and long-term stability. v0.20.0 is the Long-Term Stable (LTS) release and will receive bug fixes and security updates until v1.0 GA.
 
 ### Q: When will v1.0 be released?
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "specfact-cli"
-version = "0.19.0"
+version = "0.20.0"
 description = "Brownfield-first CLI: Reverse engineer legacy Python → specs → enforced contracts. Automate legacy code documentation and prevent modernization regressions."
 readme = "README.md"
 requires-python = ">=3.11"

setup.py

@@ -7,7 +7,7 @@
 if __name__ == "__main__":
     _setup = setup(
         name="specfact-cli",
-        version="0.19.0",
+        version="0.20.0",
         description="SpecFact CLI - Spec→Contract→Sentinel tool for contract-driven development",
         packages=find_packages(where="src"),
         package_dir={"": "src"},

src/__init__.py

@@ -3,4 +3,4 @@
 """
 
 # Define the package version (kept in sync with pyproject.toml and setup.py)
-__version__ = "0.19.0"
+__version__ = "0.20.0"

src/specfact_cli/__init__.py

@@ -9,6 +9,6 @@
 - Validating reproducibility
 """
 
-__version__ = "0.19.0"
+__version__ = "0.20.0"
 
 __all__ = ["__version__"]