Optimize context window content

[caydyan]

/claim #11

Summary

• Add a section-aware context window optimizer for repository context passed to the LLM.
• Prioritize repository structure, language summary, existing devcontainer config, and dependency/build manifest files before lower-signal sections.
• Fall back to a bounded token-prefix truncation for unstructured context.
• Keep truncate_context() as the existing call site while moving the optimization logic into a focused helper module.
• Add unit tests for priority retention, existing devcontainer retention, and plain-text fallback behavior.

Tests

python3 -m unittest tests/test_context_window_optimization.py
python3 -m unittest discover -s tests
python3 -m compileall helpers main.py tests/test_context_window_optimization.py
git diff --check

Repository note

Algora links this bounty to daytonaio/devcontainer-generator#11, but that GitHub repo path currently returns 404/disabled issues. This PR targets nibzard/devcontainer-generator, matching the existing claim PR pattern in this repo.