feat: v2.6.0 — Chat UI composer (+ menu, project files, activity panel, permission mode, Stop), git on a workspace's extra folders (#70), long paste as a file (#68), S3 server mode (experimental)

Chat UI:
- Each Claude/Codex session keeps its own chat/terminal view; Settings only
  sets how new sessions open.
- Composer + menu: upload, project files and folders (#54, also dragged from
  the Files/Changes tree), context files, recent uploads, skills, plugins.
- Activity side panel (progress, outputs, files read, uploads, memory,
  skills, connectors) with a file preview; edited-file counts per turn.
- Permission-mode chip (Shift+Tab steps, read back from the pane:
  server/lib/pane-mode.js, GET|POST /api/run/:id/permission-mode).
- Stop (Esc) while the main agent works; the status is checked per agent
  (with session_id /api/agents ignores its status filter) and re-read every
  5 s while Stop shows.
- Dropped images shown in the conversation (GET /api/run/drop/:name, the
  requester's own drop dir), full-size viewer.
- A plain-text paste over 5,000 characters is attached as pasted-text.txt,
  so no prompt reaches tmux/argv limits (#68).

Changes panel: every /api/lanes/:id/git* route takes ?source=<lane_sources
id> (sourceFolder; ENOSOURCE otherwise) and a folder picker switches the
whole panel to a workspace's extra folder (#70).

Server mode S3 (one Linux user per account) — experimental, verified with
fake sudo plus a P6 managed-settings spike on a test account:
- member tmux listing runs in the background (cached, 15 s => unknown);
- transcript snapshot copy is async, chunked, temp file + rename;
- Express Layer patch only on Express 4;
- tmux capturePane/sendKey go to the member's own server.

Docs: the multi-user design moved in as docs/plans/server-mode/README.md
(the AgentHub-Server repo is gone); S3-PLAN P6 result; LANES/API/openapi.

server/__tests__/session-name-rename.test.js

@@ -414,3 +414,47 @@ describe("GET /:id/transcript — mid-turn queued user messages (attachment/queu
     assert.equal(bySnippet("and update the docs").sender, "user");
   });
 });
+
+describe("GET /:id/transcript — what the chat needs to show live work", () => {
+  it("carries each assistant line's stop_reason and an edit result's +/- lines", async () => {
+    const cwd = "/tmp/cam-live-work";
+    const sid = "cccc1111-2222-3333-4444-555566667777";
+    writeTranscript(cwd, sid, [
+      { type: "user", message: { role: "user", content: "fix it" } },
+      {
+        type: "assistant",
+        message: {
+          role: "assistant",
+          stop_reason: "tool_use",
+          content: [{ type: "tool_use", id: "e1", name: "Edit", input: { file_path: "/w/a.ts" } }],
+        },
+      },
+      {
+        type: "user",
+        message: {
+          role: "user",
+          content: [{ type: "tool_result", tool_use_id: "e1", content: "ok" }],
+        },
+        toolUseResult: {
+          filePath: "/w/a.ts",
+          structuredPatch: [{ lines: [" a", "-b", "+c", "+d"] }],
+        },
+      },
+      {
+        type: "assistant",
+        message: {
+          role: "assistant",
+          stop_reason: "end_turn",
+          content: [{ type: "text", text: "done" }],
+        },
+      },
+    ]);
+    await req("POST", "/api/sessions", { id: sid, cwd });
+
+    const { body } = await req("GET", `/api/sessions/${sid}/transcript?limit=200`);
+    const [, call, result, done] = body.messages;
+    assert.equal(call.stop_reason, "tool_use");
+    assert.equal(done.stop_reason, "end_turn");
+    assert.deepEqual(result.content[0].diff, { added: 2, removed: 1 });
+  });
+});