docs: Add Docker section and fix repo URLs

- Added Docker instructions for testing without local install
- Fixed URLs to point to Gitea instead of GitHub

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

README.md

@@ -42,7 +42,7 @@ discussions ui --tui
 
 ```bash
 # Clone and install
-git clone https://github.com/rob/orchestrated-discussions.git
+git clone https://gitea.brrd.tech/rob/orchestrated-discussions.git
 cd orchestrated-discussions
 pip install -e ".[dev]"
 
@@ -50,10 +50,33 @@ pip install -e ".[dev]"
 pip install -e ".[tui]"
 ```
 
+## Docker
+
+Run without installing anything locally (dependencies fetched automatically):
+
+```bash
+# Clone the repo
+git clone https://gitea.brrd.tech/rob/orchestrated-discussions.git
+cd orchestrated-discussions
+
+# Build (automatically clones SmartTools from Gitea)
+docker-compose build
+
+# Run tests
+docker-compose run --rm test
+
+# Use the CLI
+docker-compose run --rm cli discussions participants
+docker-compose run --rm cli discussions status examples/brainstorm_notification_system.discussion.md
+
+# Interactive shell
+docker-compose run --rm shell
+```
+
 ### Requirements
 
 - Python 3.10+
-- [SmartTools](https://github.com/rob/smarttools) (installed automatically)
+- [SmartTools](https://gitea.brrd.tech/rob/SmartTools) (installed automatically)
 - At least one AI CLI tool (Claude, Codex, etc.)
 
 ## How It Works