feat: User profile update [⭐4xp]

Allow users to change display names and add personal information.

- [ ] Create a form modal for updating the profile
- [ ] Implement form using `react-hook-form` and `zod`
- [ ] Update data to `firestore`

## Resources
- **Sample form modal layout**
https://github.com/IndieCoderMM/convoz-chat/blob/18623b4a0524cbb557153bcbc678091ab06f9db5/src/pages/Channels.tsx#L66-L72

- **Sample form implementation** in [features/Channels/ChannelForm.tsx](https://github.com/IndieCoderMM/convoz-chat/blob/dev/src/features/Channels/ChannelForm.tsx)
- **Updating to firestore**
https://github.com/IndieCoderMM/convoz-chat/blob/18623b4a0524cbb557153bcbc678091ab06f9db5/src/features/Channels/utils.ts#L37-L42

Start by reviewing the sample modal in src/pages/Channels.tsx, the form pattern in src/features/Channels/ChannelForm.tsx, and the Firestore update in src/features/Channels/utils.ts. Use these as references for the profile form, including react-hook-form and zod validation. Done means users can change display names and personal information through the modal and the updates persist in Firestore.

Written by the indexing model from the issue text.