v0.3.4: Comment edit/delete, native notifications, forward-compatible protocol, UI fixes

Comment edit & delete:
- EditComment/DeleteComment BlobHeaderDiffOps with upstream+downstream propagation
- Trust-based: comment author can edit/delete, post author can delete
- Storage: edit_comment(), delete_comment() methods
- Frontend: inline edit (Enter/Escape), delete with confirm

Native notifications:
- tauri-plugin-notification for system notifications on all platforms
- Triggers for messages, new posts, reactions, and comments
- notif_reacts setting added, button-group toggles replace dropdowns
- _notifReady flag prevents startup spam

Protocol hardening:
- BlobHeaderDiffOp::Unknown variant with #[serde(other)] for forward compatibility
- Old nodes silently skip unknown ops instead of crashing

UI fixes:
- Self removed from Following list
- Offline follows in lightbox popup (auto-show if no one online)
- Sent DMs filtered from My Posts
- Comment threading scoped to closest .post (fixes duplicate ID issue)
- Select dropdown text legible in WebKitGTK (black on white options)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/tauri-app/src/lib.rs

@@ -1574,6 +1574,29 @@ async fn comment_on_post(
     })
 }
 
+#[tauri::command]
+async fn edit_comment(
+    state: State<'_, AppState>,
+    post_id: String,
+    timestamp_ms: u64,
+    new_content: String,
+) -> Result<(), String> {
+    let node = state.inner();
+    let pid = hex_to_postid(&post_id)?;
+    node.edit_comment(pid, timestamp_ms, new_content).await.map_err(|e| e.to_string())
+}
+
+#[tauri::command]
+async fn delete_comment(
+    state: State<'_, AppState>,
+    post_id: String,
+    timestamp_ms: u64,
+) -> Result<(), String> {
+    let node = state.inner();
+    let pid = hex_to_postid(&post_id)?;
+    node.delete_comment(pid, timestamp_ms).await.map_err(|e| e.to_string())
+}
+
 #[tauri::command]
 async fn get_comments(
     state: State<'_, AppState>,
@@ -1703,6 +1726,7 @@ pub fn run() {
 
     info!("Starting Tauri app");
     tauri::Builder::default()
+        .plugin(tauri_plugin_notification::init())
         .setup(move |app| {
             // Desktop: store data next to the AppImage/executable so each copy
             // gets its own identity. Mobile: use the standard app data dir.
@@ -1818,6 +1842,8 @@ pub fn run() {
             get_reactions,
             get_reaction_counts,
             comment_on_post,
+            edit_comment,
+            delete_comment,
             get_comments,
             set_comment_policy,
             get_comment_policy,