feat: v2.7.7 — File Explorer on workspaces and the user's home, clone with per-user git identity

- File Explorer (Files in the sidebar, /files; also from a workspace's Files
  tab, portalled so no panel clips it), laid out like GNOME Files: places
  (Home, workspaces, Trash), Back/Forward/Up, path bar, search, icon grid with
  image thumbnails or list, labelled New/Upload, selection action bar, hidden
  files behind Ctrl+H, right-click menus and the usual keys.
  Make, rename, move, copy (within a workspace, between workspaces, home ↔
  workspace), delete into a per-account trash restorable for 7 days, streamed
  upload of files and whole folders (≤ 500 MB a batch, Replace / Keep both /
  Skip on a taken name), download a file or a zip of anything.
  server/lib/file-explorer.js, /api/lanes/:id/fs/*, /api/homes/:who/fs/*.
- The user's home: every dot entry at its top stays hidden and refused
  (also via a symlink, download, zip or as a copy source); an admin may view
  other users' homes read-only, audited.
- write-as learns move/copy (re-run `sudo agenthub server install-system`).
- Hardening: a write to a workspace re-checks its owner by the live role;
  S3 keeps its server.conf if the file stops reading and a tmux call never
  falls back to the host's server; the AI Proxy gateway marks what it relays
  and the dashboard refuses it; a NUL in a pane's argv/env is refused.
- OpenAPI for the new routes (server/openapi-extra/files.js); docs (API,
  SERVER-MODE, CLAUDE.md) updated.

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

server/lib/proxy-gateway.js

@@ -34,7 +34,17 @@ const https = require("node:https");
 const IDLE_MS = 10 * 60 * 1000;
 
 /** Request headers never passed upstream: hop-by-hop, the pane's token, cookies. */
+/**
+ * Set on every request the gateway sends upstream. A personal profile may
+ * name ANY http(s) base — a loopback one included — and the gateway sends
+ * from the dashboard's own uid, which hook auth trusts. The dashboard refuses
+ * every request carrying this mark (server/index.js), so a profile pointed
+ * back at it can never reach a route as the host; a real proxy ignores it.
+ */
+const GATEWAY_MARK = "x-agenthub-via-gateway";
+
 const DROP_REQUEST = new Set([
+  GATEWAY_MARK,
   "host",
   "connection",
   "keep-alive",
@@ -151,6 +161,7 @@ function proxyGateway(req, res) {
     headers.authorization = `Bearer ${profile.apiKey}`;
     headers["x-api-key"] = profile.apiKey;
   }
+  headers[GATEWAY_MARK] = "1";
 
   const mod = target.protocol === "https:" ? https : http;
   const up = mod.request(target, { method: req.method, headers }, (answer) => {
@@ -173,4 +184,10 @@ function proxyGateway(req, res) {
   req.pipe(up);
 }
 
-module.exports = { proxyGateway, gatewayBase, setListenPort, listenPort: currentPort };
+module.exports = {
+  proxyGateway,
+  gatewayBase,
+  setListenPort,
+  listenPort: currentPort,
+  GATEWAY_MARK,
+};