Initial commit — Singular Particular Space v1

Homepage (site/index.html): integration-v14 promoted, Writings section
integrated with 33 pieces clustered by type (stories/essays/miscellany),
Writings welcome lightbox, content frame at 98% opacity.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

skills/react-native-skills/rules/animation-derived-value.md

@@ -0,0 +1,53 @@
+---
+title: Prefer useDerivedValue Over useAnimatedReaction
+impact: MEDIUM
+impactDescription: cleaner code, automatic dependency tracking
+tags: animation, reanimated, derived-value
+---
+
+## Prefer useDerivedValue Over useAnimatedReaction
+
+When deriving a shared value from another, use `useDerivedValue` instead of
+`useAnimatedReaction`. Derived values are declarative, automatically track
+dependencies, and return a value you can use directly. Animated reactions are
+for side effects, not derivations.
+
+**Incorrect (useAnimatedReaction for derivation):**
+
+```tsx
+import { useSharedValue, useAnimatedReaction } from 'react-native-reanimated'
+
+function MyComponent() {
+  const progress = useSharedValue(0)
+  const opacity = useSharedValue(1)
+
+  useAnimatedReaction(
+    () => progress.value,
+    (current) => {
+      opacity.value = 1 - current
+    }
+  )
+
+  // ...
+}
+```
+
+**Correct (useDerivedValue):**
+
+```tsx
+import { useSharedValue, useDerivedValue } from 'react-native-reanimated'
+
+function MyComponent() {
+  const progress = useSharedValue(0)
+
+  const opacity = useDerivedValue(() => 1 - progress.get())
+
+  // ...
+}
+```
+
+Use `useAnimatedReaction` only for side effects that don't produce a value
+(e.g., triggering haptics, logging, calling `runOnJS`).
+
+Reference:
+[Reanimated useDerivedValue](https://docs.swmansion.com/react-native-reanimated/docs/core/useDerivedValue)