chore: v2.8.12 — clone queue and progress, session defaults, chat agents, drops as @ mentions

Whole tree from parallel sessions, plus the version bump:
- Clone: a queue with live progress (Add workspace and extra folders),
  clones run under nice/ionice so the machine stays responsive.
- Settings → AI tools → Session defaults: a new session's default
  permission mode / bypass per account.
- Chat lists the background subagents that have not reported back yet.
- A file pasted or dropped into a claude pane goes in as an @ mention.
- Changes panel: say why amend/undo is refused on a pushed commit.
- openapi.yaml regenerated (Artifacts, Host, resumeById).

client/src/components/run/__tests__/RunSetup.test.tsx

@@ -606,4 +606,26 @@ describe("promptForPane — images apart, every other file in the text", () => {
       ],
     });
   });
+
+  it("hands claude every file as an @ mention in one paste, with a trailing space", () => {
+    // A bare pasted path stayed plain text on Windows, and a path in the
+    // command-line prompt is never an image; claude reads an @ mention at submit.
+    const images: PromptImage[] = [
+      { path: "C:\\Users\\u\\.claude\\agenthub\\drops\\f326fc666d3bdd92-image.png", name: "image.png" },
+      { path: "/data/drops/0123456789abcdef-log.txt", name: "log.txt" },
+      { path: '@"/home/u/My Docs/a.PNG"', name: "a.PNG" },
+      { path: "C:\\Users\\Jo Do\\drops\\0123456789abcdef.png", name: "b.png" },
+    ];
+    expect(promptForPane(" look ", images, true)).toEqual({
+      text:
+        'look @C:/Users/u/.claude/agenthub/drops/f326fc666d3bdd92-image.png ' +
+        '@/data/drops/0123456789abcdef-log.txt @"/home/u/My Docs/a.PNG" ' +
+        '@"C:/Users/Jo Do/drops/0123456789abcdef.png" ',
+      files: [],
+    });
+    expect(promptForPane("just text", [], true)).toEqual({ text: "just text", files: [] });
+    expect(promptWithImages("see", [images[1]!], true)).toBe(
+      "see @/data/drops/0123456789abcdef-log.txt"
+    );
+  });
 });