docs: pre-release audit and documentation improvements

- Simplify CONTRIBUTING.md for open source contributors
- Update version to 0.1.0 (Open Source) in overview
- Clarify BYO-key requirement in UI docs
- Expand open source explanation in docs/9
- Add comprehensive pre-public release audit notes

docs/6_ui.md

@@ -76,7 +76,7 @@ RA-H uses a fixed 3-panel desktop layout optimized for knowledge work.
 3. **Workflows** - Available workflows (integrate)
 4. **Logs** - Activity feed (last 100 entries)
 5. **Analytics** - Token usage and cost breakdown
-6. **API Keys** - Configure Anthropic/OpenAI/Tavily keys (beta ships with embedded keys)
+6. **API Keys** - Configure your Anthropic/OpenAI/Tavily keys (required for operation)
 
 **Logs view:**
 - Table/action filtering