feat: v2.7.8 — Artifacts hub, clone related repos as extra folders, quieter resume prompt

- Artifacts (/artifacts): claude.ai pages sessions publish (captured from the
  Artifact tool's hook), pinned workspace files, skills and plugins, each
  kept as a snapshot; shared ones appear in a Hub and a skill or plugin
  installs into the viewer's own account (server/lib/artifacts.js,
  /api/artifacts, docs/plans/artifacts/).
- Workspace extra folders: clone one or more related repos beside the
  workspace and add them in one step (POST /api/lanes/:id/sources/clone).
- A pane that ended by itself while tmux kept running is no longer offered
  for resume (tmux.serverStartedAt in reconcileOrphans).
- Changes panel: a folder that is not a git repo opens on Files, and its
  files open from there.
- Plus the parallel sessions' work in this tree: File Explorer button in the
  panel header, user delete, RSA SSH keys, chat/terminal and pet fixes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

client/src/components/conversation/__tests__/MarkdownContent.test.tsx

@@ -7,8 +7,52 @@
  */
 
 import { describe, it, expect } from "vitest";
-import { render, screen } from "@testing-library/react";
-import { MarkdownContent } from "../MarkdownContent";
+import { vi } from "vitest";
+import { fireEvent, render, screen } from "@testing-library/react";
+import { MarkdownContent, OpenFileContext } from "../MarkdownContent";
+import { resolveIn } from "../../../lib/resolvePath";
+
+function withOpen(text: string) {
+  const open = vi.fn();
+  render(
+    <OpenFileContext.Provider value={open}>
+      <MarkdownContent text={text} />
+    </OpenFileContext.Provider>
+  );
+  return open;
+}
+
+describe("file links", () => {
+  it("opens a relative path with its line suffix stripped", () => {
+    const open = withOpen("See server/lib/x.js:42 for it.");
+    fireEvent.click(screen.getByRole("button", { name: "server/lib/x.js:42" }));
+    expect(open).toHaveBeenCalledWith("server/lib/x.js");
+  });
+
+  it("opens an absolute path with a line suffix and one in inline code", () => {
+    const open = withOpen("At /a/b/c.ts:9 and `docs/API.md`.");
+    fireEvent.click(screen.getByRole("button", { name: "/a/b/c.ts:9" }));
+    fireEvent.click(screen.getByRole("button", { name: "docs/API.md" }));
+    expect(open.mock.calls).toEqual([["/a/b/c.ts"], ["docs/API.md"]]);
+  });
+
+  it("opens a markdown link to a file instead of navigating", () => {
+    const open = withOpen("[the panel](client/src/A%20B.tsx#L12) and [web](https://x.dev)");
+    fireEvent.click(screen.getByRole("button", { name: "the panel" }));
+    expect(open).toHaveBeenCalledWith("client/src/A B.tsx");
+    expect(screen.getByRole("link", { name: "web" })).toHaveAttribute("href", "https://x.dev");
+  });
+
+  it("leaves prose with slashes as text", () => {
+    withOpen("and/or, 3/4.5, github.com/x.js, TCP/IP.");
+    expect(screen.queryAllByRole("button")).toHaveLength(0);
+  });
+
+  it("resolves a relative path against the pane's folder", () => {
+    expect(resolveIn("/w/repo/", "./server/../docs/API.md")).toBe("/w/repo/docs/API.md");
+    expect(resolveIn("/w/repo", "/etc/x.conf")).toBe("/etc/x.conf");
+  });
+});
 
 describe("<MarkdownContent />", () => {
   it("renders fenced code blocks with the language label", () => {