fix: persist note_extensions on AP Update activity

on_update was discarding custom fields (posterUrl, movieTitle, etc),
so remote notes from movies-diary lost posters after Update delivery.

crates/adapters/activitypub/src/handler.rs

@@ -210,11 +210,11 @@ impl ApObjectHandler for ThoughtsObjectHandler {
         let obj_type = object.get("type").and_then(|v| v.as_str()).unwrap_or("");
         match obj_type {
             "Note" | "Article" | "Page" => {
-                let Some((note, _)) = ThoughtNote::try_from_ap(object) else {
+                let Some((note, note_extensions)) = ThoughtNote::try_from_ap(object) else {
                     return Ok(());
                 };
                 self.repo
-                    .apply_note_update(ap_id.as_str(), &note.content)
+                    .apply_note_update(ap_id.as_str(), &note.content, note_extensions)
                     .await
                     .map_err(|e| anyhow!("{e}"))
             }

crates/adapters/activitypub/src/port.rs

@@ -76,7 +76,12 @@ pub trait ActivityPubRepository: Send + Sync {
     async fn accept_note(&self, input: AcceptNoteInput<'_>) -> Result<ThoughtId, DomainError>;
 
     /// Apply an Update to a previously accepted remote Note.
-    async fn apply_note_update(&self, ap_id: &str, new_content: &str) -> Result<(), DomainError>;
+    async fn apply_note_update(
+        &self,
+        ap_id: &str,
+        new_content: &str,
+        note_extensions: Option<serde_json::Value>,
+    ) -> Result<(), DomainError>;
 
     /// Remove a specific remote Note (Delete activity). Only touches
     /// remotely-originated thoughts.