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/data_model.rs

@@ -11,9 +11,30 @@ pub struct DataModel {
     pub package_data: HashMap<String, PackageDataEntry>,
     #[serde(rename = "peer-health", default, skip_serializing_if = "HashMap::is_empty")]
     pub peer_health: HashMap<String, bool>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub notifications: Vec<Notification>,
     pub ui: UIData,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct Notification {
+    pub id: String,
+    pub level: NotificationLevel,
+    pub title: String,
+    pub message: String,
+    pub timestamp: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub app_id: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum NotificationLevel {
+    Info,
+    Warning,
+    Error,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct ServerInfo {
     pub id: String,
@@ -239,6 +260,7 @@ impl DataModel {
             },
             package_data: HashMap::new(),
             peer_health: HashMap::new(),
+            notifications: Vec::new(),
             ui: UIData {
                 name: None,
                 ack_welcome: String::new(),