fix(ui): stabilize modal keyboard behavior

TODO.md

@@ -38,3 +38,4 @@ Improving & Fixing Bugs (V3)
 - [x] Added check-up stats (correct/bad/pending) and persisted per snapshot
 - [x] Extra UI polish pass (spacing, cards, hierarchy)
 - [x] Centered and enlarged edit/check-up modals to fully overlay nav
+- [x] Fixed modal keyboard glitching (stable centered keyboard-aware layout)

src/modals/CheckupFixModal.js

@@ -15,7 +15,7 @@ export default function CheckupFixModal({
   return (
     <Modal visible={visible} animationType="slide" transparent>
       <View style={styles.modalBackdrop}>
-        <KeyboardAvoidingView behavior={Platform.OS === 'ios' ? 'padding' : 'height'} style={styles.modalKeyboardWrap}>
+        <KeyboardAvoidingView behavior={Platform.OS === 'ios' ? 'padding' : undefined} style={styles.modalKeyboardWrap}>
           <View style={styles.modalCard}>
             <View style={styles.sectionRow}>
               <Text style={styles.sectionTitle}>Update for this Check-Up</Text>
@@ -24,7 +24,12 @@ export default function CheckupFixModal({
               </Pressable>
             </View>
 
-            <ScrollView keyboardShouldPersistTaps="handled" showsVerticalScrollIndicator={false}>
+            <ScrollView
+              keyboardShouldPersistTaps="handled"
+              keyboardDismissMode="interactive"
+              contentContainerStyle={{ paddingBottom: 12 }}
+              showsVerticalScrollIndicator={false}
+            >
               <Field label="Status">
                 <ChipGroup
                   options={ITEM_STATUSES}

src/modals/ItemModal.js

@@ -16,7 +16,7 @@ export default function ItemModal({
   return (
     <Modal visible={visible} animationType="slide" transparent>
       <View style={styles.modalBackdrop}>
-        <KeyboardAvoidingView behavior={Platform.OS === 'ios' ? 'padding' : 'height'} style={styles.modalKeyboardWrap}>
+        <KeyboardAvoidingView behavior={Platform.OS === 'ios' ? 'padding' : undefined} style={styles.modalKeyboardWrap}>
           <View style={styles.modalCard}>
             <View style={styles.sectionRow}>
               <Text style={styles.sectionTitle}>{itemForm.id ? 'Update Item' : 'Add Item'}</Text>
@@ -25,7 +25,12 @@ export default function ItemModal({
               </Pressable>
             </View>
 
-            <ScrollView keyboardShouldPersistTaps="handled" showsVerticalScrollIndicator={false}>
+            <ScrollView
+              keyboardShouldPersistTaps="handled"
+              keyboardDismissMode="interactive"
+              contentContainerStyle={{ paddingBottom: 12 }}
+              showsVerticalScrollIndicator={false}
+            >
               <Field label="Name">
                 <TextInput
                   style={styles.input}

src/styles.js

@@ -400,17 +400,17 @@ export const styles = StyleSheet.create({
   modalBackdrop: {
     flex: 1,
     backgroundColor: 'rgba(2,6,23,0.72)',
-    justifyContent: 'center',
-    alignItems: 'center',
     paddingHorizontal: 12,
   },
   modalKeyboardWrap: {
+    flex: 1,
     width: '100%',
     alignItems: 'center',
+    justifyContent: 'center',
   },
   modalCard: {
     width: '96%',
-    maxHeight: '92%',
+    maxHeight: '90%',
     backgroundColor: '#0f172a',
     borderRadius: 20,
     borderWidth: 1,