refactor(mobile): use theme colors consistently

mobile/src/app/(tabs)/capture/voice.tsx

@@ -47,5 +47,5 @@ const styles = StyleSheet.create({
   transcriptBox: { backgroundColor: colors.surfaceCard, borderRadius: 8, padding: 12, borderWidth: 1, borderColor: colors.borderDefault },
   transcriptText: { fontSize: 15, color: colors.textPrimary, lineHeight: 22 },
   saveBtn: { backgroundColor: colors.accentPrimary, borderRadius: 8, paddingVertical: 8, paddingHorizontal: 16, alignItems: 'center' },
-  saveBtnText: { color: '#fff', fontWeight: '600', fontSize: 15 },
+  saveBtnText: { color: colors.onAccent, fontWeight: '600', fontSize: 15 },
 });

mobile/src/app/_layout.tsx

@@ -474,7 +474,7 @@ const styles = StyleSheet.create({
   },
   modalBackdrop: {
     flex: 1,
-    backgroundColor: 'rgba(0,0,0,0.45)',
+    backgroundColor: colors.overlayBackdrop,
     justifyContent: 'center',
     paddingHorizontal: 16,
   },

mobile/src/app/intake.tsx

@@ -11,12 +11,12 @@ import { colors } from '../theme';
 type ContentTypeBadge = { label: string; color: string };
 
 const CONTENT_TYPE_MAP: Record<string, ContentTypeBadge> = {
-  youtube: { label: 'YouTube', color: '#FF0000' },
+  youtube: { label: 'YouTube', color: colors.danger },
   article: { label: 'Article', color: colors.accentPrimary },
-  pdf: { label: 'PDF', color: '#E44D26' },
-  tweet: { label: 'Tweet', color: '#1DA1F2' },
-  reddit: { label: 'Reddit', color: '#FF4500' },
-  github: { label: 'GitHub', color: '#6e5494' },
+  pdf: { label: 'PDF', color: colors.warning },
+  tweet: { label: 'Tweet', color: colors.accentSecondary },
+  reddit: { label: 'Reddit', color: colors.warning },
+  github: { label: 'GitHub', color: colors.textSecondary },
   generic: { label: 'Web Page', color: colors.textSecondary },
 };
 

mobile/src/app/prompt-result.tsx

@@ -117,7 +117,7 @@ const styles = StyleSheet.create({
     alignItems: 'center',
   },
   btnText: {
-    color: '#fff',
+    color: colors.onAccent,
     fontWeight: '600',
     fontSize: 15,
   },

mobile/src/theme/colors.ts

@@ -14,4 +14,6 @@ export const colors = {
   success: tokensJson.color.semantic.dark.success,
   warning: tokensJson.color.semantic.dark.warning,
   danger: tokensJson.color.semantic.dark.danger,
+  onAccent: tokensJson.color.semantic.dark.textPrimary,
+  overlayBackdrop: `${tokensJson.color.semantic.dark.bgCanvas}CC`,
 } as const;