fix(next): select text from transcript gaps

tests/test-execution.toml

@@ -2175,6 +2175,14 @@ lane = "linux-guard"
 path = "tests/test_zig_fetch_all.py"
 lane = "linux-guard"
 
+[[test]]
+path = "tests/test_ci_runs_on_fallback.py"
+lane = "linux-guard"
+
+[[test]]
+path = "tests/test_workflow_file_size.py"
+lane = "linux-guard"
+
 [[test]]
 path = "tests/test_swift_linux_packages.py"
 lane = "linux-guard"

webviews/src/agent-session/acpmux/App.tsx

@@ -1776,6 +1776,10 @@ const RowFrame = React.memo(function RowFrame({
         />
       )}
       <ReferenceScopeContext.Provider value={referenceScope ?? null}>{children}</ReferenceScopeContext.Provider>
+      {/* The row's own trailing padding is the only row-local empty surface owned by transcript
+          selection. Keeping it as a separate hit target means content controls (including native
+          media) never need to be enumerated by the gap handler. */}
+      <span className="acpmux-row__gap" data-transcript-gap="row" aria-hidden="true" />
     </article>
   );
 }, sameRowFrame);

webviews/src/agent-session/acpmux/conversation/AgentMessageRow.tsx

@@ -92,7 +92,7 @@ export function AgentMessageRow({
         {/* The words toggle too, for the pointer; the toggle button is the control, and its label
             reads the line. */}
         {before.trim() && (
-          <span className="cv-agentmsg__words" aria-hidden onClick={onToggle}>
+          <span className="cv-agentmsg__words" data-interactive="" aria-hidden onClick={onToggle}>
             {before.trim()}
           </span>
         )}
@@ -107,12 +107,18 @@ export function AgentMessageRow({
             {name}
           </button>
         ) : (
-          <span className="cv-agentmsg__name is-plain" aria-hidden title={nameTitle} onClick={onToggle}>
+          <span
+            className="cv-agentmsg__name is-plain"
+            data-interactive=""
+            aria-hidden
+            title={nameTitle}
+            onClick={onToggle}
+          >
             {name}
           </span>
         )}
         {after.trim() && (
-          <span className="cv-agentmsg__words" aria-hidden onClick={onToggle}>
+          <span className="cv-agentmsg__words" data-interactive="" aria-hidden onClick={onToggle}>
             {after.trim()}
           </span>
         )}

webviews/src/agent-session/acpmux/conversation/EditedFilesCard.tsx

@@ -164,6 +164,7 @@ function Card({
         {/* oxlint-disable-next-line jsx-a11y/click-events-have-key-events, jsx-a11y/no-static-element-interactions */}
         <div
           className={single ? "acpmux-edited-title acpmux-edited-title--toggle" : "acpmux-edited-title"}
+          data-interactive={single ? "" : undefined}
           onClick={single ? toggleDiff : undefined}
         >
           <div>{title}</div>

webviews/src/agent-session/acpmux/conversation/IncomingMessageCard.tsx

@@ -284,6 +284,7 @@ export function IncomingMessageLine({
       id={bodyId}
       className="cv-received__body selectable"
       data-cut={cut || undefined}
+      data-interactive={cut ? "" : undefined}
       onClick={cut ? openCut : undefined}
     >
       {/* The chips read whose files these are (chips/messageScope.ts). */}
@@ -385,7 +386,7 @@ export function IncomingMessageLine({
             {from}
           </button>
         ) : (
-          <span className="cv-received__name is-plain" aria-hidden onClick={toggle}>
+          <span className="cv-received__name is-plain" data-interactive="" aria-hidden onClick={toggle}>
             {from}
           </span>
         )}

webviews/src/agent-session/acpmux/conversation/PreviewCard.tsx

@@ -68,7 +68,7 @@ export function PreviewCard({ url, onOpen }: { url: string; onOpen: (url: string
         </div>
       )}
       {!own && loaded && !live && (
-        <div className="acpmux-turn-preview-frame" aria-hidden="true" onClick={() => onOpen(frame)}>
+        <div className="acpmux-turn-preview-frame" data-interactive="" aria-hidden="true" onClick={() => onOpen(frame)}>
           <iframe
             src={frame}
             title={address}

webviews/src/agent-session/acpmux/conversation/conversation.css

@@ -1231,6 +1231,18 @@ pre.cv-math-source {
   left: var(--cv-inset);
   right: var(--cv-inset);
 }
+.acpmux-row__gap {
+  position: absolute;
+  z-index: 0;
+  right: 0;
+  bottom: 0;
+  left: 0;
+  height: 0;
+  /* Inherit the actual row padding: step rows and live lines use smaller or zero gaps. */
+  padding-bottom: inherit;
+  pointer-events: auto;
+  background: transparent;
+}
 /* Keyboard transcript selection uses a roving article tab stop. The fill is deliberately on the
    row rather than the prose so a range remains visible while its rows virtualize in and out. */
 .acpmux-row[data-transcript-selected="true"] {

webviews/src/agent-session/acpmux/conversation/gutterSelect.gallery.ts

@@ -5,6 +5,7 @@
 import { agentPaneEntry } from "../../../gallery/format";
 import type { PlayContext } from "../../../gallery/play";
 import { assistant, chat, summary, user } from "../../../gallery/fixtures/acpmux";
+import { GAP_KINDS, gapPair } from "./selectionGaps.fixture";
 
 const rows = [
   user("How does the keeper start the night?", 30),
@@ -35,29 +36,87 @@ function answerLine(doc: Document, text: string) {
   return undefined;
 }
 
+/// The blank vertical rhythm between the two public answer fixtures.
+function answerGap(doc: Document, above: string, below: string) {
+  const first = answerLine(doc, above);
+  const second = answerLine(doc, below);
+  if (!first || !second) return undefined;
+  return { x: (first.left + first.right) / 2, y: (first.bottom + second.top) / 2 };
+}
+
 /// Presses at `from` in the margin, drags to `to` in steps a frame apart, and lifts.
 async function drag(ctx: PlayContext, from: { x: number; y: number }, to: { x: number; y: number }) {
   const doc = ctx.document;
   const view = doc.defaultView!;
   const scroller = doc.querySelector<HTMLElement>(".acpmux-scroll")!;
-  const init = (x: number, y: number, buttons: number): MouseEventInit => ({
+  const init = (x: number, y: number, buttons: number): PointerEventInit => ({
     bubbles: true,
     cancelable: true,
     clientX: x,
     clientY: y,
     button: 0,
     buttons,
+    isPrimary: true,
+    pointerId: 1,
+    pointerType: "mouse",
   });
-  scroller.dispatchEvent(new MouseEvent("mousedown", init(from.x, from.y, 1)));
+  const target = doc.elementFromPoint(from.x, from.y) ?? scroller;
+  target.dispatchEvent(new PointerEvent("pointerdown", init(from.x, from.y, 1)));
   for (let step = 1; step <= 6; step += 1) {
     const at = (a: number, b: number) => a + ((b - a) * step) / 6;
-    view.dispatchEvent(new MouseEvent("mousemove", init(at(from.x, to.x), at(from.y, to.y), 1)));
+    view.dispatchEvent(new PointerEvent("pointermove", init(at(from.x, to.x), at(from.y, to.y), 1)));
     await new Promise((resolve) => view.requestAnimationFrame(resolve));
   }
-  view.dispatchEvent(new MouseEvent("mouseup", init(to.x, to.y, 0)));
+  view.dispatchEvent(new PointerEvent("pointerup", init(to.x, to.y, 0)));
   await ctx.waitFor(() => !(view.getSelection()?.isCollapsed ?? true), { capMs: 1500 }).catch(() => undefined);
 }
 
+const gapVariants = Object.fromEntries(
+  GAP_KINDS.flatMap((above) =>
+    GAP_KINDS.map((below) => [
+      `${above}-to-${below}-gap`,
+      {
+        note: `Drag from the gap between ${above} and ${below} rows; the nearest visible text caret starts a new native selection.`,
+        snapshot: chat(gapPair(above, below), { title: "Select through transcript gaps" }),
+        play: async (ctx: PlayContext) => {
+          // Consecutive tools intentionally have no production row gap. This fixture supplies a
+          // visible gap for that pair, as the midpoint browser regression does; content stays native.
+          if (above === "tool" && below === "tool") {
+            const style = ctx.document.createElement("style");
+            style.textContent = '.acpmux-row[data-row-id="upper"] { padding-bottom: 32px; }';
+            ctx.document.head.append(style);
+          }
+          for (const id of ["upper", "lower"]) {
+            const selector = `[data-row-id="${id}"] .cv-tool.is-toggle`;
+            if (ctx.document.querySelector(selector)) await ctx.click({ selector });
+          }
+          const rects = (id: string) => {
+            const walker = ctx.document.createTreeWalker(ctx.document.querySelector(`[data-row-id="${id}"]`)!, 4);
+            for (let node = walker.nextNode(); node; node = walker.nextNode()) {
+              if (!node.textContent?.startsWith(`${id} keeper`)) continue;
+              const range = ctx.document.createRange();
+              range.selectNodeContents(node);
+              const boxes = Array.from(range.getClientRects());
+              if (boxes.length) return boxes;
+            }
+            throw new Error(`No visible ${id} text`);
+          };
+          const after = rects("after")[0]!;
+          const upper = ctx.document.querySelector<HTMLElement>('[data-row-id="upper"]')!;
+          const column = upper.getBoundingClientRect();
+          const padding = Number.parseFloat(ctx.document.defaultView!.getComputedStyle(upper).paddingBottom);
+          await drag(
+            ctx,
+            { x: (column.left + column.right) / 2, y: column.bottom - Math.max(1, padding / 2) },
+            { x: after.left + 180, y: after.top + after.height / 2 },
+          );
+          if (ctx.document.getSelection()?.isCollapsed) throw new Error("Gap drag selected no text");
+        },
+      },
+    ]),
+  ),
+);
+
 export default agentPaneEntry({
   id: "agent-pane.gutter-select",
   title: "Drag-select from the margin",
@@ -67,6 +126,11 @@ export default agentPaneEntry({
   anchors: [{ selector: ".acpmux-scroll" }],
   covers: ["agent-session/acpmux/App.tsx#VirtualTranscript"],
   variants: {
+    ...gapVariants,
+    "gaps-ready": {
+      note: "Public agent message fixtures for the same before/after gap-selection capture; the pair variants also cover tools and prompts.",
+      snapshot: chat(gapPair("agent", "agent"), { title: "Select through transcript gaps" }),
+    },
     "from-left-margin": {
       note: "Pressed in the left margin beside the first answer and dragged down into the third: the selection runs from the start of the line beside the press through all three answers, as a document's margin selects.",
       snapshot: chat(rows, { title: "Drag-select from the margin" }),
@@ -89,5 +153,15 @@ export default agentPaneEntry({
         await drag(ctx, { x: (third.right + width - 16) / 2, y: third.bottom }, { x: first.left + 300, y: first.top });
       },
     },
+    "from-row-gap": {
+      note: "Pressed in the blank rhythm between the first two answers and dragged into the second: the nearest mounted caret starts the native range instead of leaving a dead zone.",
+      snapshot: chat(rows, { title: "Drag-select from a row gap" }),
+      play: async (ctx) => {
+        const gap = answerGap(ctx.document, "Alpha", "Bravo");
+        const second = answerLine(ctx.document, "Bravo");
+        if (!gap || !second) return;
+        await drag(ctx, gap, { x: second.left + 300, y: second.top + 4 });
+      },
+    },
   },
 });