0.4.0: JSON/HTML snapshot output via freeze-snapshot-convert; GUI 'Open in browser' button

README.md

@@ -150,6 +150,21 @@ The GUI's **Live graphs** tab shows the last hour of load, PSI io/cpu, and D-sta
 
 Click "📸 Capture Now" in the GUI status bar (or in the tray menu) to trigger a snapshot immediately, regardless of whether thresholds are crossed. Useful when you suspect something is brewing but it hasn't tripped the alarms.
 
+## JSON / HTML output
+
+Set `OUTPUT_JSON=1` and/or `OUTPUT_HTML=1` in `/etc/freeze-watcher.conf` to write structured sidecars next to each text snapshot:
+
+- **JSON** (`snap-*.json`) — fully structured: PSI, dstate procs, kernel stacks, memory, top procs, cgroup PSI, softirqs, etc. Easy to consume programmatically.
+- **HTML** (`snap-*.html`) — self-contained styled report with color-coded metrics, collapsible sections, and clickable kernel stacks per D-state proc. Useful for sharing or pasting into a bug report.
+
+You can also convert any existing snapshot manually:
+
+```
+freeze-snapshot-convert /var/log/freeze-watcher/snap-20260510-214207.log --json --html
+```
+
+The GUI's "Open in browser" button on the Snapshots tab opens the HTML sidecar of the selected snapshot (generating it on demand if missing).
+
 ## Future ideas
 
 - Web UI option (no Qt requirement)