Fix auto-lookback trigger and add version tracking (#20)

* Fix auto-lookback trigger and add version tracking

- Trigger on stdin inactivity instead of render time
- Only dump when new output exists since last dump
- Default timeout 5s -> 15s
- Embed git hash in version output
- Document macOS config path

Cargo.toml

@@ -5,6 +5,6 @@ members = [
 ]
 
 [workspace.package]
-version = "0.1.0"
+version = "0.1.1"
 edition = "2024"
 authors = ["David Beesley"]