fix(fe): handle Discord embed thumbnail/image as plain URL string in serde deserialization

The Discord embed metadata sometimes returns thumbnail/image fields as
plain URL strings (e.g., "thumbnail":"https://...") instead of the
expected object format ({"url":"...","width":...,"height":...}).

Since serde deserializes the entire PageResult<MessageRecord> in one call,
even one message with a string-format embed field caused the entire response
to fail, making the message section appear empty despite the API returning
valid data.

Added a custom deserializer deser_embed_media that accepts null, a string
(interpreted as URL), or an object (standard struct deserialization).
Applied to both image and thumbnail fields in EmbedInfo with #[serde(default)]
so missing fields don't error. Includes 5 unit tests covering all formats.

services/frontend/shared-types/src/lib.rs

@@ -5,3 +5,77 @@ pub mod media;
 pub mod dashboard;
 pub mod recording;
 pub mod ui_state;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_embed_media_string() {
+        // Simulate what Discord sends: thumbnail as a plain URL string
+        let json = r#"{"title":"Test","thumbnail":"https://cdn.example.com/image.gif"}"#;
+        let embed: message::EmbedInfo = serde_json::from_str(json).unwrap();
+        assert_eq!(embed.title, Some("Test".into()));
+        let thumb = embed.thumbnail.unwrap();
+        assert_eq!(thumb.url, "https://cdn.example.com/image.gif");
+        assert_eq!(thumb.width, None);
+        assert_eq!(thumb.height, None);
+    }
+
+    #[test]
+    fn test_embed_media_object() {
+        // Standard embed media object
+        let json = r#"{"thumbnail":{"url":"https://cdn.example.com/img.png","width":128,"height":128}}"#;
+        let embed: message::EmbedInfo = serde_json::from_str(json).unwrap();
+        let thumb = embed.thumbnail.unwrap();
+        assert_eq!(thumb.url, "https://cdn.example.com/img.png");
+        assert_eq!(thumb.width, Some(128));
+        assert_eq!(thumb.height, Some(128));
+    }
+
+    #[test]
+    fn test_embed_media_null() {
+        let json = r#"{"title":"No Media Here"}"#;
+        let embed: message::EmbedInfo = serde_json::from_str(json).unwrap();
+        assert_eq!(embed.thumbnail, None);
+        assert_eq!(embed.image, None);
+    }
+
+    #[test]
+    fn test_embed_media_both_strings() {
+        // Discord might send both image and thumbnail as strings 
+        let json = r#"{"image":"https://cdn.example.com/banner.gif","thumbnail":"https://cdn.example.com/thumb.gif"}"#;
+        let embed: message::EmbedInfo = serde_json::from_str(json).unwrap();
+        assert_eq!(embed.image.as_ref().unwrap().url, "https://cdn.example.com/banner.gif");
+        assert_eq!(embed.thumbnail.as_ref().unwrap().url, "https://cdn.example.com/thumb.gif");
+    }
+
+    #[test]
+    fn test_full_message_metadata_with_string_thumbnail() {
+        // Full realistic metadata with string thumbnail (the actual bug)
+        let json = r#"{
+            "stickers": [],
+            "embeds": [{
+                "title": "Meisho Doto Tm Opera O",
+                "description": null,
+                "url": "https://klipy.com/gifs/test",
+                "color": null,
+                "image": null,
+                "thumbnail": "https://static.klipy.com/ii/test.webp",
+                "author": null,
+                "footer": null,
+                "fields": []
+            }]
+        }"#;
+        let meta: message::MessageMetadata = serde_json::from_str(json).unwrap();
+        let embeds = meta.embeds.unwrap();
+        assert_eq!(embeds.len(), 1);
+        let embed = &embeds[0];
+        assert_eq!(embed.title.as_deref(), Some("Meisho Doto Tm Opera O"));
+        assert!(embed.image.is_none());
+        let thumb = embed.thumbnail.as_ref().unwrap();
+        assert_eq!(thumb.url, "https://static.klipy.com/ii/test.webp");
+        assert_eq!(thumb.width, None);
+        assert_eq!(thumb.height, None);
+    }
+}

services/frontend/shared-types/src/message.rs

@@ -64,17 +64,42 @@ pub struct AttachmentRef {
     pub content_type: Option<String>,
 }
 
+/// Deserialize `EmbedMedia` from either:
+///   - `null` → `None`
+///   - a JSON string → `Some(EmbedMedia { url: <string>, width: None, height: None })`
+///   - a JSON object → standard struct deserialization
+fn deser_embed_media<'de, D: Deserializer<'de>>(d: D) -> Result<Option<EmbedMedia>, D::Error> {
+    let v = Option::<serde_json::Value>::deserialize(d)?;
+    match v {
+        None => Ok(None),
+        Some(serde_json::Value::String(s)) => Ok(Some(EmbedMedia {
+            url: s,
+            width: None,
+            height: None,
+        })),
+        Some(obj) => serde_json::from_value(obj).map(Some).map_err(de::Error::custom),
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct EmbedInfo {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub title: Option<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(
+        default,
+        deserialize_with = "deser_embed_media",
+        skip_serializing_if = "Option::is_none"
+    )]
     pub image: Option<EmbedMedia>,
-    #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(
+        default,
+        deserialize_with = "deser_embed_media",
+        skip_serializing_if = "Option::is_none"
+    )]
     pub thumbnail: Option<EmbedMedia>,
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[derive(Debug, Clone, Serialize, PartialEq)]
 pub struct EmbedMedia {
     pub url: String,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -83,6 +108,28 @@ pub struct EmbedMedia {
     pub height: Option<u32>,
 }
 
+impl<'de> Deserialize<'de> for EmbedMedia {
+    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
+        // When EmbedMedia appears as a struct member (inside the object branch
+        // of deser_embed_media), serde calls this directly. We delegate to a
+        // derived deserializer on the struct fields.
+        #[derive(serde::Deserialize)]
+        struct Inner {
+            url: String,
+            #[serde(default)]
+            width: Option<u32>,
+            #[serde(default)]
+            height: Option<u32>,
+        }
+        let inner = Inner::deserialize(d)?;
+        Ok(EmbedMedia {
+            url: inner.url,
+            width: inner.width,
+            height: inner.height,
+        })
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct ChannelRef {
     pub channel_id: String,