v0.4.0 — Index-first compact context

Threadbase 0.4.0 introduces an index-first workflow for lower-token agent usage in larger repos.

What’s new:

• Added .ai/generated/index.md as a compact routing layer
• Kept .ai/generated/context.md focused on current state instead of file discovery
• Added size budgets in .ai/config.yml
• Updated prompts, rules, and adapters to read the index first
• Reduced always-on context size for long-running repositories

This makes Threadbase more efficient as repo memory grows over time.