adding ability to record logs for debug purposes

README.md

@@ -210,6 +210,50 @@ The data includes: names of active adapters/providers, OS, architecture, Node ve
 
 **Thanks**🤘
 
+## 🐞 Debug Information
+
+Since Fredy **22.5.0** there is a built-in way to capture everything Fredy logs into the
+database for a limited time and download it as a single zip file. This is the recommended
+way to attach diagnostics to a bug report. I decided against simply putting all logs into
+a debug bundle due to privacy reasons!
+
+**How it works**
+
+- Debug logging is **opt-in** and admin-only. As long as it is off, Fredy behaves exactly
+  as before (console output only, nothing in the DB).
+- When you turn it on, every log line (`debug`, `info`, `warn`, `error`) is additionally
+  written into the `debug_logs` SQLite table. The console keeps logging at its usual level.
+- The recorded data is hard-capped at **5 MiB** via a rolling buffer: once the cap is hit,
+  the oldest entries are dropped automatically so the newest ones always survive.
+- The on/off flag is persisted, so debug logging stays on across restarts (and you'll see
+  the warning banner everywhere until you turn it off again).
+
+**Capturing a debug bundle**
+
+1. Open Fredy as an **admin** and go to **Settings → Debug**.
+2. Click **"Enable debug logging" / "Debug-Logging aktivieren"**. A red banner appears on
+   every page while recording is on.
+3. **Reproduce the bug**.
+4. Come back to **Settings → Debug** and check the progress bar, if it stayed at 0 %,
+   nothing was captured.
+5. Click **"Download debug information" / "Debug Informationen herunterladen"**. You get a
+   zip named `YYYY-MM-DD-FredyDebug-<version>.zip` containing two files:
+   - `logs.txt` - every log line captured while recording was on, prefixed with timestamp
+     and level.
+   - `sys.txt` - runtime snapshot (Fredy version, Node.js version, OS, Docker detection,
+     CPU, memory, sanitized settings). Proxy credentials and session secrets are
+     **stripped** before export.
+6. Attach the zip to the bug report.
+7. Optional but recommended: click **"Disable debug logging"** to stop recording, and
+   **"Delete stored debug logs"** once you've sent the zip so the DB does not keep them
+   around.
+
+**What is _not_ included**
+
+- passwords/privacy relevant things
+- Anything that Fredy itself does not pass through its `logger`. If a third-party library
+  writes directly to `process.stderr`, that output stays on the console only.
+
 ## 🛠️ Development
 
 ### Development Mode