Make Cobble a local install: setup flow, bots-first admin, settings

Local, password-only auth:
- No public pages; everything outside /admin and /auth redirects in
- First run (no users) sends every page to /auth/signup, which creates
  the super admin (user #1) once and then locks
- Login is email/username + password; removed the emailed-code flow,
  /auth/sso and email password reset
- Google login kept for existing accounts only, never creates them
- seed-super-admin now requires SEED_SUPER_ADMIN_PASSWORD

Bots-first admin:
- /admin and closed sections (people, logs, backups) redirect to
  /admin/bots; only bots and settings are live (AdminSections)
- Removed the old admin layout; every /admin page uses the bots rail
- Coordinator bot created at signup/seed and by /admin/bots
  (ensureCoordinatorBot), which redirects to its chat
- bots.system_prompt (markdown) with a default coordinator prompt
- seed-bots reuses the existing coordinator

Settings:
- Sub pages general (default), profile, change-password, listed in the
  rail with a back link; unknown settings paths redirect to general
- Redesigned settings UI: pane header, grouped rows, sticky save bar
- General: System/Light/Dark theme, saved per device

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

src/pages/auth/logout/index.server.ts

@@ -32,10 +32,6 @@ export const server: BunextPageServerFn = async ({ req }) => {
                     name: AppData["AuthCSRFCookieName"],
                     httpOnly: true,
                 },
-                {
-                    name: AppData["SSOAuthCookieName"],
-                    httpOnly: true,
-                },
             ]);
             return new_res;
         },

src/pages/auth/logout/index.tsx

@@ -14,7 +14,7 @@ import { SiteData } from "@/src/data/site-data";
 export default function LogoutPage() {
     useEffect(() => {
         setTimeout(() => {
-            window.location.pathname = "/";
+            window.location.pathname = "/auth/login";
         }, 1000);
     }, []);
 
@@ -43,5 +43,5 @@ export default function LogoutPage() {
 
 export const meta: BunextPageModuleMeta = {
     title: `Logging Out | ${SiteData["SiteName"]}`,
-    description: "You are being logged out and redirected to the homepage.",
+    description: "You are being logged out and redirected to the login page.",
 };