Give more credit to ccusage as inspiration and dependency

ccusage by @ryoppippi is the foundation for our usage tracking feature.
Added attribution in README and docs with links to the project and author.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dtran320

README.md

@@ -292,7 +292,9 @@ VibeReps includes built-in skills you can run in Claude Code:
 
 ## 📊 Usage Statistics
 
-Track your Claude Code usage alongside exercise data with `vibereps-usage.py`:
+Track your Claude Code usage alongside exercise data with `vibereps-usage.py`.
+
+Built on top of [**ccusage**](https://github.com/ryoppippi/ccusage) by [@ryoppippi](https://github.com/ryoppippi) - a fantastic tool for tracking Claude Code token usage and costs. Our usage script was inspired by ccusage's clean table format and adds exercise tracking alongside your coding stats.
 
 ```bash
 ./vibereps-usage.py
@@ -302,7 +304,7 @@ Track your Claude Code usage alongside exercise data with `vibereps-usage.py`:
   <img src="assets/vibereps-usage.gif" alt="vibereps-usage demo" width="800">
 </p>
 
-This combines [ccusage](https://github.com/ryoppippi/ccusage) output with your exercise log into a single table:
+Combines ccusage output with your exercise log into a single table:
 
 ```
 ┌────────────┬───────────────────────────────────────┬───────────┬───────────┬───────────────┬──────────────┬───────────────┬─────────────┬───────────────────────────┐

docs/advanced/monitoring.md

@@ -6,6 +6,17 @@ View your Claude Code usage alongside exercise data with `vibereps-usage`.
   <img src="/vibereps-usage.gif" alt="vibereps-usage demo" style="max-width: 100%; border-radius: 8px; box-shadow: 0 4px 12px rgba(0,0,0,0.15);">
 </p>
 
+## Powered by ccusage
+
+This feature is built on [**ccusage**](https://github.com/ryoppippi/ccusage) by [@ryoppippi](https://github.com/ryoppippi) - an excellent CLI tool for tracking Claude Code token usage and costs. We were inspired by ccusage's clean table format and built `vibereps-usage.py` to add exercise data alongside your coding stats.
+
+If you just want Claude Code usage tracking without exercise data, ccusage is all you need:
+
+```bash
+npm install -g ccusage
+ccusage daily
+```
+
 ## Quick Start
 
 ```bash