feat: add ccusage for Claude Code usage monitoring

## Summary

Integrate [ccusage](https://github.com/ryoppippi/ccusage) - a CLI tool for analyzing Claude Code token usage and costs from local JSONL files. This will help monitor rate limits and plan usage effectively.

## Features to Add

- **Installation**: Add ccusage to `utils/install-claude-code.sh`
- **Aliases**: Create convenient aliases in `.bash_aliases.d/ai-tools.sh`:
- `ccus` → `ccusage daily` (quick daily report)
- `ccusl` → `ccusage blocks --live` (live monitoring)
- `ccusm` → `ccusage monthly` (monthly summary)
- **Documentation**: Add usage tips to Claude Code setup output

## Benefits

- Track token usage and costs by day/month/session
- Monitor 5-hour billing windows
- Real-time usage dashboard
- Per-model cost breakdown
- Offline mode support
- MCP server integration

## Implementation

Will be added to the existing `feature/claude-code-integration` branch.

## References

- ccusage repo: https://github.com/ryoppippi/ccusage (1.7k stars)
- Documentation: https://ccusage.com/

Start by reading utils/install-claude-code.sh and .bash_aliases.d/ai-tools.sh, then locate the Claude Code setup output mentioned in the issue. Verify how existing tools are installed, aliased, and documented. Done means ccusage is installed, all three aliases work, and the setup output includes usage tips.

Written by the indexing model from the issue text.