docs: update README with container preservation feature

- Add documentation for --preserve-containers-on-failure flag
- Include usage examples for both CLI and TUI modes
- Explain when and how containers are preserved for debugging
- Add example of the helpful debugging message users will see
- Update CLI examples section to showcase the new feature

README.md

@@ -90,6 +90,9 @@ wrkflw run --emulate .github/workflows/ci.yml
 
 # Run with verbose output
 wrkflw run --verbose .github/workflows/ci.yml
+
+# Preserve failed containers for debugging
+wrkflw run --preserve-containers-on-failure .github/workflows/ci.yml
 ```
 
 ### Using the TUI Interface
@@ -223,6 +226,23 @@ WRKFLW supports composite actions, which are actions made up of multiple steps.
 
 WRKFLW automatically cleans up any Docker containers created during workflow execution, even if the process is interrupted with Ctrl+C.
 
+For debugging failed workflows, you can preserve containers that fail by using the `--preserve-containers-on-failure` flag:
+
+```bash
+# Preserve failed containers for debugging
+wrkflw run --preserve-containers-on-failure .github/workflows/build.yml
+
+# Also available in TUI mode
+wrkflw tui --preserve-containers-on-failure
+```
+
+When a container fails with this flag enabled, WRKFLW will:
+- Keep the failed container running instead of removing it
+- Log the container ID and provide inspection instructions
+- Show a message like: `Preserving container abc123 for debugging (exit code: 1). Use 'docker exec -it abc123 bash' to inspect.`
+
+This allows you to inspect the exact state of the container when the failure occurred, examine files, check environment variables, and debug issues more effectively.
+
 ## Limitations
 
 ### Supported Features