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>

core/archipelago/src/api/rpc/update.rs

@@ -42,4 +42,52 @@ impl RpcHandler {
         update::dismiss_update(&self.config.data_dir).await?;
         Ok(serde_json::json!({ "ok": true }))
     }
+
+    /// Download the available update to staging.
+    pub(super) async fn handle_update_download(&self) -> Result<serde_json::Value> {
+        let progress = update::download_update(&self.config.data_dir).await?;
+        Ok(serde_json::json!({
+            "total_bytes": progress.total_bytes,
+            "downloaded_bytes": progress.downloaded_bytes,
+            "components_downloaded": progress.components_downloaded,
+        }))
+    }
+
+    /// Apply the staged update.
+    pub(super) async fn handle_update_apply(&self) -> Result<serde_json::Value> {
+        update::apply_update(&self.config.data_dir).await?;
+        Ok(serde_json::json!({ "applied": true, "restart_required": true }))
+    }
+
+    /// Rollback to the previous version.
+    pub(super) async fn handle_update_rollback(&self) -> Result<serde_json::Value> {
+        update::rollback_update(&self.config.data_dir).await?;
+        Ok(serde_json::json!({ "rolled_back": true, "restart_required": true }))
+    }
+
+    /// Get the current update schedule.
+    pub(super) async fn handle_update_get_schedule(&self) -> Result<serde_json::Value> {
+        let schedule = update::get_schedule(&self.config.data_dir).await?;
+        Ok(serde_json::json!({ "schedule": schedule }))
+    }
+
+    /// Set the update schedule. Params: { schedule: "manual" | "daily_check" | "auto_apply" }
+    pub(super) async fn handle_update_set_schedule(
+        &self,
+        params: &serde_json::Value,
+    ) -> Result<serde_json::Value> {
+        let schedule_str = params["schedule"]
+            .as_str()
+            .ok_or_else(|| anyhow::anyhow!("Missing 'schedule' parameter"))?;
+
+        let schedule = match schedule_str {
+            "manual" => update::UpdateSchedule::Manual,
+            "daily_check" => update::UpdateSchedule::DailyCheck,
+            "auto_apply" => update::UpdateSchedule::AutoApply,
+            _ => anyhow::bail!("Invalid schedule: '{}'. Use manual, daily_check, or auto_apply", schedule_str),
+        };
+
+        update::set_schedule(&self.config.data_dir, schedule).await?;
+        Ok(serde_json::json!({ "schedule": schedule }))
+    }
 }