feat(terminal): add per-tab auto-fold toggle to block menu

src/lib/components/TerminalPane.svelte

@@ -224,6 +224,11 @@
     let paintScheduler: PaintScheduler | undefined;
     let paintTick = $state(0);
     let isAltBuffer = $state(false);
+    // Per-tab: when true the fold store stops auto-folding new output (see
+    // shouldAutoFold below). Existing folds stay untouched; flip back to fold
+    // future output again. Survives reconnect and tab switches; resets only
+    // when the tab closes (this keyed component instance is destroyed).
+    let autoFoldDisabled = $state(false);
 
     function schedulePaintTick() {
         paintScheduler?.schedule();
@@ -536,6 +541,12 @@
                     disabled: n === 0 || !aiConfigured,
                     action: () => sendBlocksToAi(targets),
                 },
+                {
+                    label: t(autoFoldDisabled
+                        ? "terminal.block.menu.enable_auto_fold"
+                        : "terminal.block.menu.disable_auto_fold"),
+                    action: () => { autoFoldDisabled = !autoFoldDisabled; },
+                },
             ],
         };
     }
@@ -1645,6 +1656,9 @@
             maxVisibleLines: commandBlockMaxLines,
             maxCachedLines: commandBlockFoldCacheLines(commandBlockMaxLines),
             shouldAutoFold: () => app.commandBlockBar(),
+            // Per-tab "disable auto-fold" suspends folding of NEW output only;
+            // enforceAutoFold (resize/reflow) still restores existing folds.
+            shouldFoldNewOutput: () => !autoFoldDisabled,
         });
         paintScheduler = createPaintScheduler({
             shouldPaint: () => app.commandBlockBar() && !isAltBuffer,

src/lib/i18n/locales/en.ts

@@ -230,6 +230,8 @@ const en = {
   "terminal.block.menu.uncolor": "Remove color",
   "terminal.block.menu.send_ai": "Send to AI",
   "terminal.block.menu.send_ai_n": "Send {n} blocks to AI",
+  "terminal.block.menu.disable_auto_fold": "Disable auto-fold (this tab)",
+  "terminal.block.menu.enable_auto_fold": "Enable auto-fold (this tab)",
   "ai.mobile.hint": "Tip: rotate to landscape for the AI panel. Tools download_file / analyze_locally are unavailable on this build.",
   "ai.no_session": "Connect to a terminal before opening the AI panel.",
   "settings.section.cli": "CLI Tool",

src/lib/i18n/locales/zh.ts

@@ -232,6 +232,8 @@ const zh: Messages = {
   "terminal.block.menu.uncolor": "取消染色",
   "terminal.block.menu.send_ai": "发送到 AI",
   "terminal.block.menu.send_ai_n": "发送 {n} 块到 AI",
+  "terminal.block.menu.disable_auto_fold": "临时关闭自动折叠（当前标签）",
+  "terminal.block.menu.enable_auto_fold": "开启自动折叠（当前标签）",
   "ai.mobile.hint": "建议横屏使用 AI 面板。本机型不支持 download_file / analyze_locally 两个工具。",
   "ai.no_session": "请先连接到一个终端再打开 AI 面板。",
   "settings.section.cli": "CLI 工具",

src/lib/terminal/folds.test.ts

@@ -911,6 +911,56 @@ describe("FoldStore — automatic command-block limit", () => {
     expect(f.lineContents().slice(0, 4)).toEqual(["L0", "L8", "L9", "L10"]);
   });
 
+  it("does not fold new output while new-output folding is disabled (bar still on)", () => {
+    const f = fakeTerm({ rows: 12, initialLines: 12, cursorY: 10 });
+    const start = f.makeMarker(0);
+    const store = createFoldStore(
+      f.term,
+      fakeTracker([makeBlock(1, start, null)]),
+      { maxVisibleLines: 3, maxCachedLines: 8, shouldFoldNewOutput: () => false },
+    );
+
+    f.fireWriteParsed();
+
+    // shouldFoldNewOutput=false suspends incremental folding; the block stays
+    // fully visible even though it exceeds maxVisibleLines.
+    expect(store.getFold(1)).toBeUndefined();
+    expect(f.lineContents().slice(0, 4)).toEqual(["L0", "L1", "L2", "L3"]);
+  });
+
+  it("keeps an existing fold through resize/reflow while new-output folding is disabled", () => {
+    const f = fakeTerm({ rows: 12, initialLines: 12, cursorY: 10 });
+    const start = f.makeMarker(0);
+    let newOutputEnabled = true;
+    const store = createFoldStore(
+      f.term,
+      fakeTracker([makeBlock(1, start, null)]),
+      {
+        maxVisibleLines: 3,
+        maxCachedLines: 8,
+        shouldFoldNewOutput: () => newOutputEnabled,
+      },
+    );
+
+    // 1. Auto-fold on: a block over the limit gets prefix-folded.
+    f.fireWriteParsed();
+    expect(store.getFold(1)).toMatchObject({ kind: "prefix", count: 7 });
+
+    // 2. User disables auto-fold for this tab (future output only).
+    newOutputEnabled = false;
+
+    // 3. fitTerminal resize sequence: unfoldAll (so saved lines reflow at the
+    //    new width) then enforceAutoFold. Disabling new-output folding must NOT
+    //    block the reflow re-application, or the existing fold is lost.
+    store.unfoldAll();
+    expect(store.getFold(1)).toBeUndefined();
+    store.enforceAutoFold();
+
+    // 4. The existing fold is restored.
+    expect(store.getFold(1)).toMatchObject({ kind: "prefix", count: 7 });
+    expect(f.lineContents().slice(0, 4)).toEqual(["L0", "L8", "L9", "L10"]);
+  });
+
   it("folds during a large parse batch before xterm can trim the block marker", () => {
     const f = fakeTerm({ rows: 40, initialLines: 40, cursorY: 3 });
     const start = f.makeMarker(0);

src/lib/terminal/folds.ts

@@ -80,6 +80,10 @@ export interface FoldStoreOptions {
   maxCachedLines?: number;
   /** Visual block controls must be available before automatic folding hides rows. */
   shouldAutoFold?: () => boolean;
+  /** Suspend folding of *new* output only. enforceAutoFold (the resize/reflow
+   *  re-application) is unaffected, so existing folds survive a resize while a
+   *  per-tab "disable auto-fold" toggle suspends folding of future output. */
+  shouldFoldNewOutput?: () => boolean;
 }
 
 /** xterm 默认 attr（fg=0,bg=0），与 DEFAULT_ATTR_DATA 等价。getBlankLine 必填。 */
@@ -316,6 +320,14 @@ export function createFoldStore(
       && term.buffer.active.type === "normal";
   }
 
+  /** Incremental folding of newly arriving output. Stricter than canAutoFold:
+   *  also honors shouldFoldNewOutput so a per-tab "disable auto-fold" toggle
+   *  suspends folding of future output WITHOUT disabling enforceAutoFold,
+   *  which must still restore folds after a resize/reflow. */
+  function canFoldNewOutput(): boolean {
+    return canAutoFold() && options.shouldFoldNewOutput?.() !== false;
+  }
+
   function foldBlockOverflow(block: CommandBlock, minimumExcess: number): void {
     if (maxVisibleLines === null || block.start.isDisposed) return;
     if (folds.get(block.id)?.kind === "full") return;
@@ -332,13 +344,13 @@ export function createFoldStore(
   }
 
   function foldActiveOverflow(minimumExcess: number): void {
-    if (!canAutoFold()) return;
+    if (!canFoldNewOutput()) return;
     const block = tracker.blocks[tracker.blocks.length - 1];
     if (block?.end === null) foldBlockOverflow(block, minimumExcess);
   }
 
   function foldRecentOverflow(): void {
-    if (!canAutoFold()) return;
+    if (!canFoldNewOutput()) return;
     const blocks = tracker.blocks;
     // Prompt detection runs before this listener and may close the previous
     // block while opening a new prompt block in the same parse batch.