docs: update deprecated toolInvocations to parts

[AbhishekManjunath98]

Here’s an enhanced commit description with before and after sections in Markdown:

Refactor: Replace toolInvocations with parts in message rendering

Changes:

• Replaced deprecated toolInvocations with parts in message rendering logic.
• Ensured compatibility with the latest API from useChat.

Before:

<ScrollView style={{ flex: 1 }}>
  {messages.map(m => (
    <View key={m.id} style={{ marginVertical: 8 }}>
      <View>
        <Text style={{ fontWeight: 700 }}>{m.role}</Text>
        {m.toolInvocations ? (
          <Text>{JSON.stringify(m.toolInvocations, null, 2)}</Text>
        ) : (
          <Text>{m.content}</Text>
        )}
      </View>
    </View>
  ))}
</ScrollView>

After:

<ScrollView style={{ flex: 1 }}>
  {messages.map(m => (
    <View key={m.id} style={{ marginVertical: 8 }}>
      <View>
        <Text style={{ fontWeight: 700 }}>{m.role}</Text>
        {m.parts ? (
          <Text>{JSON.stringify(m.parts, null, 2)}</Text>
        ) : (
          <Text>{m.content}</Text>
        )}
      </View>
    </View>
  ))}
</ScrollView>

Why:

• toolInvocations has been deprecated in favor of parts.
• Aligns message rendering with the latest useChat API changes.

Impact:

• Ensures compatibility with future updates.
• Prevents breaking changes due to deprecated properties.

This keeps the commit message clear, structured, and easy to understand. 🚀