move aspect ratio to atom (#9171)

src/alf/atoms.ts

@@ -1,6 +1,7 @@
 import {type StyleProp, type ViewStyle} from 'react-native'
 import {atoms as baseAtoms} from '@bsky.app/alf'
 
+import {CARD_ASPECT_RATIO} from '#/lib/constants'
 import {native, platform, web} from '#/alf/util/platform'
 import * as Layout from '#/components/Layout'
 
@@ -31,6 +32,16 @@ export const atoms = {
     backgroundColor: 'transparent',
   },
 
+  /**
+   * Aspect ratios
+   */
+  aspect_square: {
+    aspectRatio: 1,
+  },
+  aspect_card: {
+    aspectRatio: CARD_ASPECT_RATIO,
+  },
+
   /*
    * Transition
    */
@@ -67,7 +78,7 @@ export const atoms = {
   }),
 
   /*
-   * Animaations
+   * Animations
    */
   fade_in: web({
     animation: 'fadeIn ease-out 0.15s',