Disable the fold button when no run is long enough to fold

src/App.vue

@@ -164,6 +164,7 @@ function toggleRun(hash: string) {
 }
 
 function toggleCollapseAll() {
+  if (!built.value.collapsible) return showToast("nothing to fold: no run of 3 or more plain commits");
   collapseAll.value = !collapseAll.value;
   toggled.value = new Set();
 }
@@ -244,7 +245,13 @@ onUnmounted(() => {
       <span v-if="repo" class="path">{{ repo.root }}</span>
       <span class="spacer" />
       <span v-if="repo" class="stats">{{ visibleCommits.length }} commits · {{ visibleRefs.length }}/{{ repo.refs.length }} refs</span>
-      <button class="collapse" :class="{ on: collapseAll }" title="c" @click="toggleCollapseAll">
+      <button
+        class="collapse"
+        :class="{ on: collapseAll && built.collapsible }"
+        :disabled="!built.collapsible"
+        :title="built.collapsible ? 'c' : 'Nothing to fold: no run of 3 or more commits without a branch, tag or merge'"
+        @click="toggleCollapseAll"
+      >
         <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" stroke-width="1.6" stroke-linecap="round">
           <circle cx="8" cy="2.5" r="1.6" />
           <circle cx="8" cy="13.5" r="1.6" />
@@ -362,6 +369,7 @@ onUnmounted(() => {
 .spacer { flex: 1; }
 .stats { color: var(--text-dim); font-size: 12px; }
 .collapse { display: inline-flex; align-items: center; gap: 6px; }
+.collapse:disabled { opacity: 0.4; cursor: default; background: none; }
 .collapse.on { border-color: var(--accent); color: var(--accent); background: #b197fc1a; }
 .main { flex: 1; display: flex; min-height: 0; }
 .list { flex: 1; overflow: auto; position: relative; }