refactor: split app into modular src architecture

src/tabs/HistoryTab.js

@@ -0,0 +1,36 @@
+import React from 'react';
+import { Pressable, Text, View } from 'react-native';
+import { styles } from '../styles';
+
+export default function HistoryTab({ selectedTripCheckups, selectedCheckupId, setSelectedCheckupId }) {
+  return (
+    <View style={styles.section}>
+      <Text style={styles.sectionTitle}>History</Text>
+      {selectedTripCheckups.length === 0 ? <Text style={styles.muted}>No check-ups saved yet.</Text> : null}
+
+      {selectedTripCheckups.map((checkup) => (
+        <View key={checkup.id} style={styles.cardSoft}>
+          <Pressable onPress={() => setSelectedCheckupId((prev) => (prev === checkup.id ? null : checkup.id))}>
+            <Text style={styles.cardTitle}>{new Date(checkup.createdAt).toLocaleString()}</Text>
+            <Text style={styles.cardMeta}>{checkup.snapshot.length} items</Text>
+            <Text style={styles.cardMeta}>{selectedCheckupId === checkup.id ? 'Tap to collapse' : 'Tap to open'}</Text>
+          </Pressable>
+
+          {selectedCheckupId === checkup.id ? (
+            <View style={styles.snapshotWrap}>
+              {checkup.snapshot.map((entry) => (
+                <View key={entry.itemId} style={styles.snapshotRow}>
+                  <Text style={styles.snapshotTitle}>{entry.name}</Text>
+                  <Text style={styles.cardMeta}>
+                    {entry.status} · {entry.placement}
+                    {entry.status === 'lent-to' && entry.lentTo ? ` · ${entry.lentTo}` : ''}
+                  </Text>
+                </View>
+              ))}
+            </View>
+          ) : null}
+        </View>
+      ))}
+    </View>
+  );
+}