Fix/auto generate jwt secret (#94)

* fix: auto-generate JWT_SECRET at startup if not provided
- Add ensureJwtSecret() in instrumentation.ts to generate random 64-char secret
- Mark JWT_SECRET as non-required in secretsValidator
- Remove fatal error log for missing JWT_SECRET in proxy.ts
Fixes login failure when running via CLI without JWT_SECRET env var.

* feat: improve auth flow and login page UX
- Add setupComplete to settings validation schema for proper persistence
- Support ?tab= query param in settings page for direct tab navigation
- Redesign login page with professional two-column layout
- Add context-aware states for onboarding/password setup flows
- Smooth animations and refined visual hierarchy

* fix: 404 page to use primary color theme (coral red) instead of purple

src/shared/utils/secretsValidator.ts

@@ -32,8 +32,8 @@ const SECRET_RULES = [
   {
     name: "JWT_SECRET",
     minLength: 32,
-    required: true,
-    description: "JWT signing secret for dashboard authentication",
+    required: false,
+    description: "JWT signing secret for dashboard authentication (auto-generated if not set)",
     generateHint: "openssl rand -base64 48",
   },
   {