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/parse-template-lines.test.ts

@@ -0,0 +1,16 @@
+import { describe, expect, test } from "bun:test";
+import parseTemplateLines, { templateLines } from "./parse-template-lines";
+
+describe("parseTemplateLines", () => {
+    test("reads headers, keeping colons in values", () => {
+        expect(
+            parseTemplateLines({ text: "Authorization: Bearer {{env.T}}\n\nX-Url: http://a:1\nbad line", separator: ":" }),
+        ).toEqual({ Authorization: "Bearer {{env.T}}", "X-Url": "http://a:1" });
+    });
+
+    test("reads envs and writes them back", () => {
+        const map = parseTemplateLines({ text: "A=1\nB = x=y", separator: "=" });
+        expect(map).toEqual({ A: "1", B: "x=y" });
+        expect(templateLines({ map, separator: "=" })).toBe("A=1\nB=x=y");
+    });
+});