docs: drop the invented 'Mocha Archive Terminal' name

- DESIGN.md frontmatter no longer names the design system
- The spec now references the local DESIGN.md file instead of the
  Stitch-internal design system placeholder

frontend/DESIGN.md

@@ -1,5 +1,4 @@
 ---
-name: Mocha Archive Terminal
 colors:
   surface: '#121221'
   surface-dim: '#121221'

frontend/design.md_j621_frontend_spec.md

@@ -3,7 +3,7 @@
 > **Version:** the git commit hash of the build (e.g. `3f35330`)  
 > **Theme Foundation:** Catppuccin Mocha + e621 Authentic Taxonomy Architecture  
 > **Target Platform:** Desktop-first, fully responsive self-hosted home-server media web application (the library is a watched folder on disk, not a NAS appliance)  
-> **Reference Design System:** `Mocha Archive Terminal` (`{{DATA:DESIGN_SYSTEM:DESIGN_SYSTEM_3}}`)
+> **Reference Design System:** `DESIGN.md` (this folder)
 
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