Add initial mobile support

[aimerib]

This change is a bit scary. I'm opening it as a draft because I figured I'd get the code out of my local machine and let people look at it so we could make it nice.

I'm adding your list of desired features from #39 here as a guide to walk towards:

• [x] The main screen should be just the prompt box and image result area
• [ ] A button on the left to pull up the parameters list, which pops up to cover the screen and you can edit then swipe it back away
• [x] You can pull up the other menus (image history / model browser / etc) and they also temporarily take over the full screen while you use them.

Goal: Basically take all the current UI features that are placed into cells, and swap them to being sub-screens to swap between, with the 'main prompt + result' area as the centerpoint

Of the list above:

• I've right now made everything a single column, so there's a lot of scrolling, but I tried to add some logic to jump around to logical points (when in mobile only). I like your idea much better, but that's a much bigger lift. I'm happy to works toward that in this PR before promoting it out of draft.
• Regarding a button on the left, what size of screens are we targeting with that? There's a fine line between target hit area and screen real estate on an iphone 11 for example, so I tried to shy away from anything on the edges, but only because I wasn't creative enough to come up with a clean way to do anything else. A clearly labeled area that can be tapped without interrupting thumb navigation would be really clean!
• So, a little bit like the native fly-out/fly-up pages/screens on native apps?

Things I still need to work on and would like maybe some help/pointers:

• [ ] Size of batch image container is bigger than viewport, even if image is centered on the screen fine. Have to fix the sizing there and remove overflow
• [ ] The FAB button supports long-press for an extra context menu but for some reason I'm not able to replicate that correctly in the browser simulator, but I'll take a screencap of it working on my phone. Just plain weird.
• [ ] The behavior around dragging the top bars is a little wonky right now. All that math was too hard for me at midnight after a long day of parenting. I'll get back to it soon.

Current progres:

https://github.com/user-attachments/assets/31c30436-c807-48e8-874c-b4e29f5c6c3a