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.

client/src/lib/projectTreePrefs.ts

@@ -2,7 +2,7 @@
  * @file projectTreePrefs — the sidebar workspace list's viewer preferences, in
  * ONE localStorage key (`agenthub.sidebar.projects`): which workspaces are
  * expanded to their sessions (by lane id), the tool the list is filtered to,
- * and — Settings → Worktrees —
+ * which owner groups an admin/analyst folded, and — Settings → Worktrees —
  * whether a workspace home's Add folder suggests the repo's untracked
  * worktrees and which sources of them (`claude` = `<repo>/.claude/worktrees/*`,
  * `agenthub` = LANES_ROOT) it leaves out. A `useSyncExternalStore` reader that caches nothing
@@ -20,6 +20,8 @@ export interface ProjectTreePrefs {
   expanded: Record<string, boolean>;
   /** Show only this tool's workspaces; null = every tool. */
   tool: string | null;
+  /** Server mode, admin/analyst: owner key (user id, or "none") → its group is folded. */
+  collapsedOwners: Record<string, boolean>;
   showUntracked: boolean;
   hideSources: string[];
 }
@@ -27,6 +29,7 @@ export interface ProjectTreePrefs {
 const DEFAULTS: ProjectTreePrefs = {
   expanded: {},
   tool: null,
+  collapsedOwners: {},
   showUntracked: true,
   hideSources: [],
 };
@@ -50,6 +53,10 @@ export function readProjectTreePrefs(): ProjectTreePrefs {
     value = {
       expanded: parsed.expanded && typeof parsed.expanded === "object" ? parsed.expanded : {},
       tool: typeof parsed.tool === "string" && parsed.tool ? parsed.tool : null,
+      collapsedOwners:
+        parsed.collapsedOwners && typeof parsed.collapsedOwners === "object"
+          ? parsed.collapsedOwners
+          : {},
       showUntracked: parsed.showUntracked !== false,
       hideSources: Array.isArray(parsed.hideSources) ? parsed.hideSources : [],
     };