Add MCP servers and custom tools for bots

Two new settings pages, MCPs and Tools. Super admins define them; super
admins and admins attach them to bots, to workspaces (every bot there),
or to every bot. Bots get them in chat replies and tasks.

- Custom tools: a JSON-schema of arguments plus an HTTP request, a script
  on the bot's computer, or a prompt, templated with {{args.x}} and
  {{env.KEY}}, secrets redacted from results.
- MCP servers: remote (URL and headers) or stdio commands run on the host
  with a setup command and an isolated env, in a per-process pool. Tools
  are listed into a cache and connect on first call.
- Add, edit, access and try open in modals.
- Markdown, JSON and command fields use twui's AceEditor (CodeEditor),
  its scripts loaded on demand.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/pages/admin/settings/(utils)/extension-access-label.ts

@@ -0,0 +1,22 @@
+import type { ExtensionAccess } from "@/src/types";
+
+type Params = {
+    access: ExtensionAccess;
+};
+
+/**
+ * Who gets an MCP server or tool, in a few words: "Every bot",
+ * "2 bots · 1 workspace", or "No bots yet".
+ */
+export default function extensionAccessLabel({ access }: Params) {
+    if (access.all_bots) return "Every bot";
+
+    const parts = [
+        access.bot_ids.length ? `${access.bot_ids.length} ${access.bot_ids.length == 1 ? "bot" : "bots"}` : "",
+        access.workspace_ids.length
+            ? `${access.workspace_ids.length} ${access.workspace_ids.length == 1 ? "workspace" : "workspaces"}`
+            : "",
+    ].filter(Boolean);
+
+    return parts.join(" · ") || "No bots yet";
+}