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>

.claude/memory/MEMORY.md

@@ -0,0 +1,11 @@
+# Archipelago Project Memory Index
+
+- [pending-features.md](pending-features.md) — Feature requests: kiosk mode, sideloading, Nostr login, etc.
+- [second-server.md](second-server.md) — Second dev server (archipelago-2 via Tailscale)
+- [third-server.md](third-server.md) — Third dev server (archipelago-3 via Tailscale)
+- [deploy-automation.md](deploy-automation.md) — Deploy script automation TODOs
+- [claude-proxy-setup.md](claude-proxy-setup.md) — Claude proxy OAuth setup details
+- [project-plan.md](project-plan.md) — Overall project plan status
+- [iso-build-session-2026-03-10.md](iso-build-session-2026-03-10.md) — ISO build session notes
+- [unbundled-iso.md](unbundled-iso.md) — Unbundled ISO approach notes
+- [web-only-apps.md](web-only-apps.md) — Web-only apps (L484 category) and iframe compatibility