fix(electrobun): load CanvasAddon+ImageAddon AFTER term.open() (fixes _linkifier2 crash)

ui-electrobun/src/mainview/Terminal.svelte

@@ -50,8 +50,16 @@
 
     fitAddon = new FitAddon();
     term.loadAddon(fitAddon);
-    term.loadAddon(new CanvasAddon());
+    // NOTE: CanvasAddon and ImageAddon MUST be loaded AFTER term.open()
+    // because they access _linkifier2 which is created during open()
 
+    const openAndLoadAddons = () => {
+      term.open(termEl);
+      // Now safe to load addons that depend on _linkifier2
+      try { term.loadAddon(new CanvasAddon()); } catch (e) {
+        console.warn('[Terminal] CanvasAddon failed:', (e as Error).message);
+      }
+      try {
         term.loadAddon(new ImageAddon({
           enableSizeReports: true,
           sixelSupport: true,
@@ -59,30 +67,24 @@
           sixelPaletteLimit: 4096,
           showPlaceholder: true,
         }));
-
-    // Defer open if container isn't visible yet (e.g., behind splash)
-    const tryOpen = () => {
-      try {
-        term.open(termEl);
-        fitAddon.fit();
       } catch (e) {
-        console.warn('[Terminal] open failed, retrying in 500ms:', (e as Error).message);
-        setTimeout(tryOpen, 500);
+        console.warn('[Terminal] ImageAddon failed:', (e as Error).message);
       }
+      fitAddon.fit();
     };
+
+    // Defer if container isn't visible yet (e.g., behind splash)
     if (termEl.offsetParent !== null) {
-      tryOpen();
+      openAndLoadAddons();
     } else {
-      // Container not visible — wait for it
       const observer = new IntersectionObserver((entries) => {
         if (entries[0]?.isIntersecting) {
           observer.disconnect();
-          tryOpen();
+          openAndLoadAddons();
         }
       });
       observer.observe(termEl);
-      // Fallback: try after 2s regardless
-      setTimeout(() => { observer.disconnect(); tryOpen(); }, 2000);
+      setTimeout(() => { observer.disconnect(); openAndLoadAddons(); }, 2000);
     }
 
     // ── Read cursor/scrollback settings ─────────────────────────────────