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/functions/backend/db/extensions/grab-mcp-server.ts

@@ -0,0 +1,24 @@
+import BunSQLite from "@moduletrace/bun-sqlite";
+import type { BUN_SQLITE_COBBLE_MCP_SERVERS } from "@/db/types/db";
+import AppError from "@/src/utils/app-error";
+import parseMcpServerRow from "./parse-mcp-server-row";
+
+type Params = {
+    mcp_server_id: number | string;
+};
+
+/**
+ * One MCP server, or an `AppError` when there's none.
+ */
+export default async function grabMcpServer({ mcp_server_id }: Params) {
+    const row = (
+        await BunSQLite.sql<BUN_SQLITE_COBBLE_MCP_SERVERS>({
+            sql: `SELECT * FROM mcp_servers WHERE id = ?`,
+            values: [mcp_server_id],
+        })
+    ).payload?.[0];
+
+    if (!row) throw new AppError(`That MCP server doesn't exist.`);
+
+    return parseMcpServerRow({ row });
+}