New design doc: Architecture of material_ui and cupertino_ui (#13529)

Add `/go/material-ui-cupertino-ui-architecture` design doc redirect.

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Co-authored-by: Parker Lougheed <parlough@gmail.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: 3 people

firebase.json

@@ -614,6 +614,7 @@
       { "source": "/go/material-date-picker-redesign", "destination": "https://docs.google.com/document/d/1AGKjBvO7EL2PuJGcwaa2PoCusjtTAvpYO7i_3A2vVpc/edit", "type": 301 },
       { "source": "/go/material-symbols", "destination": "https://docs.google.com/document/d/1UHRKDl8-lzl_hW_K2AHnpMwvdPo0vGPbDI7mqACWXJY/edit?usp=sharing", "type": 301 },
       { "source": "/go/material-theme-system-updates", "destination": "https://docs.google.com/document/d/1kzIOQN4QYfVsc5lMZgy_A-FWGXBAJBMySGqZqsJytcE/edit", "type": 301 },
+      { "source": "/go/material-ui-cupertino-ui-architecture", "destination": "https://docs.google.com/document/d/1TW42GcjEWoPZK7Y2cZr38zjoRQ1T4gJBujXIqPL_lOw/edit?usp=sharing", "type": 301 },
       { "source": "/go/max-length-enforcement", "destination": "https://docs.google.com/document/d/1S900lQaTPOsePnIeE7o3-Ia8f39VZaSv0JnjNyBfCvU", "type": 301 },
       { "source": "/go/medium-sized-code-samples", "destination": "https://docs.google.com/document/d/1-jjYru2ljRSRSY4hn4qwLj9oQj8UiqrDOgY10-FE2tY/edit?usp=sharing", "type": 301 },
       { "source": "/go/migrate-flutter-wiki", "destination": "https://docs.google.com/document/d/1naONKJd-eqPj8zEVfHfjGa5TCZNyJErBY4ca1gjSCq4/edit?usp=sharing", "type": 301 },