Feature Request: Pinned chats, folders, archive, notes, assistant and more

Hi! I have some feature suggestions to make DekuSMS much better. Most of these are inspired by Telegram and other modern messengers.

I don't know English well, so I'm using a translator. I hope you can understand me at least a little.

I know these are a lot of features, but even implementing 2-3 of them would be a huge improvement.
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# 1. Chat pinning
- Make it possible to pin chats from above, please. And so that pinned chats can be dragged with a finger - one above, the other below, as you want.
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# 2. Folders for chats
- I want to create folders myself (for example, "Work", "Friends", "Family"). I want each folder to have its own pinned chats.
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# 3. Archive with pull-out
- In the inbox folder, make a small hidden "Archive" bar on top. When you pull the chat list down (as if you're refreshing), this bar appears. Click on it to open the archive. If you release it and the bar goes up behind the screen, it disappears. It's similar to Telegram.
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# 4. Local notes (Saved messages)
## Make a separate chat "Notes" or "Saved", which is stored only on the phone. So that you can:
- forward any messages from other chats there;
- write your notes there;
- forwarded messages were displayed on the other side and the number, as if they were sent by someone else (so that it was clear that it was forwarded).
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# 5. Assistant on the device
## Add something like a system bot that can:
- send important notifications from the developer or phone;
- automatically answer some questions;
- have buttons with ready-made questions (for example, "Help", "What can you do?", "Status") and ready-made answers to them.
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# 6. Scheduled messages
- Write a message now and set a specific date/time for it to be sent automatically.
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# 7. Customization & appearance
- Different themes and color schemes for chat bubbles.
- Set custom background images for individual chats.
- Custom notification sounds for specific contacts (so you know who messaged without looking).

## Thanks for considering these! I know it's a lot, but even a few of these would make DekuSMS the best free open source SMS app out there.

The issue contains seven independent feature proposals but names no files, tests, or entry points. Start by narrowing the request to one feature and confirm its scope with maintainers; it is done only when that feature has explicit acceptance criteria and focused tests or manual verification steps.

Written by the indexing model from the issue text.