Add auth bootstrap and database safeguards

docs/DESIGN_SYSTEM.md

@@ -9,6 +9,9 @@ This document defines the visual language for SHD.build. New pages should feel l
 3. **Orange means action.** SHD orange identifies primary actions, active navigation, focus, and important values. It should not cover large areas.
 4. **State is always visible.** Loading, disabled, active, archived, configured, error, and success states need both visual and textual indicators.
 5. **Square and engineered.** Panels and controls use square corners, fine borders, tight spacing, and deliberate grid alignment.
+6. **Links use interface feedback, not underlines.** Links do not use native text
+   underlines. Communicate hover and focus through SHD accent color, borders,
+   brightness, and the required focus-visible outline.
 
 ## Tokens
 
@@ -62,6 +65,21 @@ Use the spacing tokens for new components. Prefer `8px`, `12px`, and `20px` gaps
 - On small screens, the split frame becomes a single column and account controls
   move before archival content.
 
+### Third-party identity buttons
+
+- Follow the identity provider's current official brand and sign-in guidelines.
+- Use official, unmodified assets downloaded from the provider's brand resources.
+- Discord sign-in uses the official white Discord symbol on Blurple `#5865F2`
+  with the explicit label “Continue with Discord.”
+- Discord account connection controls use the same official symbol and Blurple
+  treatment with the explicit label “Link Discord.”
+- Preserve the provider's required clearspace, logo proportions, approved color,
+  readable contrast, and text/logo alignment even when the surrounding surface
+  follows the SHD theme.
+- Provider buttons still require SHD.build's focus-visible, pressed, pending, and
+  duplicate-interaction protection where those states do not conflict with the
+  provider's branding requirements.
+
 ### Admin dashboard
 
 - Use `admin-page`, `admin-command`, `admin-dashboard`, `admin-sidebar`, and `admin-content`.