v0.3.1

Audit fixes, docs alignment, and hardening.

Security & hardening:

• Fix max_tokens 8096→8192 in Claude client
• Fix _rel() leaking absolute paths outside workspace
• Fix glob results escaping workspace via symlinks/.\.
• Fix credential files written world-readable (chmod 0o600)
• Add bash command length limit (MAX_BASH_CMD_BYTES)
• Add env overrides for all OAuth client IDs/secrets
• Improve retry error context for HTTP errors

Docs:

• Align README to actual system prompt and tool descriptions
• Add chat command to README
• Add project URLs to pyproject.toml
• Sync CONTRIBUTING.md env var list
• Condense ISSUES.md resolved items into summary table

Tests:

• Add tests for _rel outside-workspace placeholder
• Add test for save_json file permissions