chore: maintenance — dependency majors, rename step 4, member Claude config, OpenAPI coverage

Dependencies
- Security: body-parser and multer DoS advisories fixed (npm audit: 0).
- Server: Express 5 (query parser kept "extended", req.body defaults to {},
  SPA catch-all /{*splat}, send-file helper restores Express 4's dot-folder
  rule for sendFile/download, alerts ack route without inline regex),
  better-sqlite3 13, js-yaml 5 (server/lib/yaml.js keeps js-yaml 4's default
  schema), uuid dropped for crypto.randomUUID, node-pty beta.18, multer 2.5.
- Client: React 19, xterm 6 (WebGL renderer replaces the removed canvas one,
  DOM fallback on context loss; Alt+arrow word moves re-mapped), lucide-react 1,
  TypeScript 7, i18next/react-i18next/codemirror minors.

Workspace rename step 4
- `agenthub lanes` and `--lane` exit 1 with "renamed: use …"; client api.ts,
  the CLI and the MCP server call /api/workspaces; /api/lanes stays mounted.

Server mode (S3): members manage their own Claude Code config
- server/lib/cc-target.js resolves whose config a /cc-config request touches
  and gates the router by allowlist; /profiles* and /plugins/update-all stay
  admin-only. Member writes go through write-as, CLI calls through sudo as the
  member (never -y), reads through openSafe; cc_config_changed reaches only
  its owner. Not verified live on an S3 install yet.

Other
- Chat: an HTML file is an artifact only when written whole and not a project
  page (index.html, or under src/, public/, templates/, …).
- OpenAPI covers every /api route; openapi-coverage.test.js guards it.
- read-pool test keeps its event loop alive (its worker is unref'd).
- Docs: plan statuses, checklists, CLI.md, LANES.md, SERVER-MODE.md, API.md.

server/routes/pets.js

@@ -48,7 +48,7 @@ router.get("/:id/sprite", (req, res) => {
     res.set("Content-Type", file.type);
     res.set("X-Content-Type-Options", "nosniff");
     res.set("Cache-Control", "private, max-age=3600");
-    res.sendFile(file.path);
+    require("../lib/send-file").sendFile(res, file.path);
   } catch (err) {
     sendError(res, err);
   }