QoL: Quick create a character book
Related to https://github.com/luminai-companion/agn-ai/pull/116
If I want to write down a memory, I have to exit the chat, create a book, write the memory, and go back to the chat, assign the book to the character.
It would be nice to just click on "Create" in the chat memory.

To avoid cluttering the books page, I suggest:
- Ability to assign a book to a specific character, or a specific chat
- The Memory page only lists global books or character-specific books
- Chat-specific books will be deleted along with the chat
- When creating the book in the chat, you can choose the scope (global, character, or chat)
- Only one character book and one chat book can be assigned
(By the way I create all these issues with the intent of working on some of them, if there's support for this)
By the way, books have keywords AND a title... I'm wondering, is the title useful? I end up having to just write things twice. I'd get rid of the title personally, and I'd also remove the option to collapse the blocks, as I find they make it harder to navigate the content of the page.