refactor(tests): reformat code and update dependency management

- Reorganized import statements in adapter tests for better readability
- Replaced or_insert_with(Vec::new) with or_default() in test closures
- Updated Cargo.lock with new dependency versions and checksums
- Added TLS features to tonic dependency configuration
- Included sqlx, chrono, and uuid dependencies with specific features
- Added jsonwebtoken and arc-swap as project dependencies
- Reformatted assertion statements to comply with line length limits
- Adjusted base64 import order in engine codec module
- Updated protobuf include statement formatting

models/message_edit.rs

@@ -0,0 +1,77 @@
+//! Message edit history — maps to `message_edit` table.
+//!
+//! Immutable append-only log of every edit to a message.
+//! Used for audit trails, "edited" indicators with hover-to-see-original,
+//! and compliance / moderation review.
+
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+/// One edit record. Stored every time a message body is modified.
+#[derive(Debug, Clone, Serialize, Deserialize, sqlx::FromRow)]
+pub struct MessageEdit {
+    pub id: Uuid,
+    pub message_id: Uuid,
+    /// Who made the edit (usually the author; can be a moderator).
+    pub edited_by: Uuid,
+    /// Body content before the edit.
+    pub old_body: String,
+    /// Body content after the edit.
+    pub new_body: String,
+    pub edited_at: DateTime<Utc>,
+}
+
+/// Lightweight summary for the "edited" tooltip (no full body).
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct EditSummary {
+    pub edit_count: i64,
+    pub last_edited_at: Option<DateTime<Utc>>,
+    pub last_edited_by: Option<Uuid>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_message_edit_serialize() {
+        let edit = MessageEdit {
+            id: Uuid::now_v7(),
+            message_id: Uuid::now_v7(),
+            edited_by: Uuid::now_v7(),
+            old_body: "before edit".to_string(),
+            new_body: "after edit".to_string(),
+            edited_at: Utc::now(),
+        };
+
+        let json = serde_json::to_value(&edit).unwrap();
+        assert_eq!(json["old_body"], "before edit");
+        assert_eq!(json["new_body"], "after edit");
+    }
+
+    #[test]
+    fn test_edit_summary_serialize() {
+        let summary = EditSummary {
+            edit_count: 3,
+            last_edited_at: Some(Utc::now()),
+            last_edited_by: Some(Uuid::now_v7()),
+        };
+
+        let json = serde_json::to_value(&summary).unwrap();
+        assert_eq!(json["edit_count"], 3);
+    }
+
+    #[test]
+    fn test_edit_summary_no_edits() {
+        let summary = EditSummary {
+            edit_count: 0,
+            last_edited_at: None,
+            last_edited_by: None,
+        };
+
+        let json = serde_json::to_value(&summary).unwrap();
+        assert_eq!(json["edit_count"], 0);
+        assert!(json["last_edited_at"].is_null());
+    }
+}