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_sticker.rs

@@ -0,0 +1,56 @@
+//! Sticker attachment on a message — maps to `message_sticker` table.
+//!
+//! Large sticker images sent in messages, distinct from emoji reactions.
+//! Stickers are either workspace-level (custom, defined in appks) or
+//! system-level (built-in sticker packs).
+
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+/// A sticker attached to a message.
+///
+/// Maps to the `message_sticker` table. Stickers are larger than emoji
+/// and can be workspace-level (custom) or system-level (built-in packs).
+#[derive(Debug, Clone, Serialize, Deserialize, sqlx::FromRow)]
+pub struct MessageSticker {
+    pub id: Uuid,
+    pub message_id: Uuid,
+    /// References a sticker defined in appks (workspace or system sticker).
+    pub sticker_id: Uuid,
+    /// Sticker name at time of send (snapshot for history).
+    pub name: String,
+    /// Image URL (snapshot).
+    pub image_url: String,
+    /// "png" | "apng" | "lottie"
+    pub format_type: String,
+    /// Pack name (e.g. "Wumpus" or workspace name).
+    pub pack_name: Option<String>,
+    /// Search tags for discovery.
+    pub tags: Option<String>,
+    pub created_at: DateTime<Utc>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sticker_serialize() {
+        let s = MessageSticker {
+            id: Uuid::now_v7(),
+            message_id: Uuid::now_v7(),
+            sticker_id: Uuid::now_v7(),
+            name: "Hype!".into(),
+            image_url: "https://cdn.example.com/stickers/hype.png".into(),
+            format_type: "png".into(),
+            pack_name: Some("Wumpus".into()),
+            tags: Some("excited,hype".into()),
+            created_at: Utc::now(),
+        };
+
+        let json = serde_json::to_value(&s).unwrap();
+        assert_eq!(json["name"], "Hype!");
+        assert_eq!(json["format_type"], "png");
+    }
+}