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/utils/mcp-tool-name.ts

@@ -0,0 +1,18 @@
+type Params = {
+    /**
+     * The server's slug (`mcp_servers.slug`).
+     */
+    slug: string;
+    /**
+     * The tool's name on the server.
+     */
+    name: string;
+};
+
+/**
+ * What a bot calls an MCP server's tool: `<slug>__<tool>`, only letters,
+ * numbers, `_` and `-`, at most 64 characters (what providers accept).
+ */
+export default function mcpToolName({ slug, name }: Params) {
+    return `${slug}__${name.replace(/[^A-Za-z0-9_-]/g, "_")}`.slice(0, 64);
+}