refactor: update dependencies and remove unused code

- Added new dependencies: `adler2`, `crc32fast`, `flate2`, `miniz_oxide`, and `libredox`.
- Updated existing dependencies: `tokio-rustls` to version 0.26.4 and `filetime` to version 0.2.27.
- Removed the `backup.rs` file as it is no longer needed.
- Introduced tests for configuration and credential management.
- Enhanced the `identity` module to generate W3C compliant DID documents.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/arm64-rpi5-testing.md

@@ -0,0 +1,78 @@
+# ARM64 Raspberry Pi 5 Testing Guide
+
+## Prerequisites
+
+- Raspberry Pi 5 (4GB+ RAM recommended)
+- USB flash drive (16GB+) for the installer
+- MicroSD card or NVMe SSD for the target install
+- Monitor + keyboard (or serial console for headless setup)
+- Ethernet connection (WiFi can be configured after install)
+
+## Building the ARM64 ISO
+
+On the build server (192.168.1.228):
+
+```bash
+cd ~/archy/image-recipe
+sudo ARCH=arm64 ./build-auto-installer-iso.sh
+# Output: results/archipelago-installer-arm64.iso
+```
+
+## Flashing to USB
+
+```bash
+# On macOS
+diskutil list  # identify USB drive
+diskutil unmountDisk /dev/diskN
+sudo dd if=results/archipelago-installer-arm64.iso of=/dev/rdiskN bs=4m
+
+# On Linux
+sudo dd if=results/archipelago-installer-arm64.iso of=/dev/sdX bs=4M status=progress
+```
+
+Or use Balena Etcher for a GUI approach.
+
+## Testing Checklist
+
+### Boot & Install
+- [ ] RPi 5 boots from USB drive (may need to enable USB boot in EEPROM)
+- [ ] Auto-installer detects target disk (NVMe/SD)
+- [ ] Installation completes without errors
+- [ ] System reboots into installed OS
+
+### First Boot
+- [ ] Archipelago service starts (`systemctl status archipelago`)
+- [ ] Nginx starts and serves UI
+- [ ] Web UI loads in browser at `http://<pi-ip>`
+- [ ] Onboarding flow completes
+- [ ] Login works with default password
+
+### Container Stack
+- [ ] Podman runs on ARM64 (`podman version`)
+- [ ] Bitcoin Knots installs and syncs
+- [ ] LND installs and connects to Bitcoin
+- [ ] Electrs installs and indexes
+- [ ] Mempool installs and shows data
+- [ ] FileBrowser installs and serves files
+
+### Performance
+- [ ] Backend response time < 200ms for RPC calls
+- [ ] UI renders smoothly (no jank)
+- [ ] Container startup time reasonable (< 30s per app)
+- [ ] Memory usage stable (no leaks over 24h)
+
+## Known RPi 5 Considerations
+
+1. **USB Boot**: RPi 5 needs EEPROM update for USB boot. Run `sudo rpi-eeprom-update` on a stock Raspberry Pi OS first.
+2. **NVMe**: RPi 5 supports NVMe via the M.2 HAT. Recommended for performance.
+3. **Power**: Use the official 27W USB-C power supply. Underpowered supplies cause throttling.
+4. **Thermals**: Consider a heatsink or active cooling case for sustained Bitcoin node operation.
+5. **Storage**: Bitcoin blockchain requires ~600GB+. Use NVMe or external SSD.
+
+## Reporting Issues
+
+Document any ARM64-specific issues found during testing:
+- Architecture-specific container failures
+- Performance differences vs x86_64
+- Hardware compatibility problems
+- Missing kernel modules or firmware