v4.0.0 - 🎉 Major Release: Full Codex Max Support & Prompt Engineering Overhaul

This release brings full GPT-5.1 Codex Max support with dedicated prompts, plus complete parity with Codex CLI's prompt selection logic.

🚀 Highlights

• Full Codex Max support with dedicated prompt including frontend design guidelines
• Model-specific prompts matching Codex CLI's prompt selection logic
• GPT-5.0 → GPT-5.1 migration as legacy models are phased out by OpenAI

✨ Model-Specific System Prompts

The plugin now fetches the correct Codex prompt based on model family, matching Codex CLI's model_family.rs logic:

Model Family	Prompt File	Lines	Use Case
gpt-5.1-codex-max*	gpt-5.1-codex-max_prompt.md	117	Codex Max with frontend design guidelines
gpt-5.1-codex*, codex-*	gpt_5_codex_prompt.md	105	Focused coding prompt
gpt-5.1*	gpt_5_1_prompt.md	368	Full behavioral guidance

🔄 Legacy GPT-5.0 → GPT-5.1 Migration

All legacy GPT-5.0 models automatically normalize to GPT-5.1 equivalents:

• gpt-5-codex → gpt-5.1-codex
• gpt-5 → gpt-5.1
• gpt-5-mini, gpt-5-nano → gpt-5.1
• codex-mini-latest → gpt-5.1-codex-mini

🔧 Technical Improvements

• New ModelFamily type: "codex-max" | "codex" | "gpt-5.1"
• Lazy instruction loading: Instructions fetched per-request based on model
• Separate caching per family: Better cache efficiency
• Model family logging: Debug with modelFamily field in logs

🧪 Test Coverage

• 191 unit tests (16 new for model family detection)
• 13 integration tests with family verification
• All tests passing ✅

📝 Full Changelog

See CHANGELOG.md for complete details.

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Installation:
```bash
npm install [email protected]
```