pre-commit: Check for images exceeding 4096×4096

[wjt]

As documented in
https://github.com/endlessm/threadbare/wiki/Visual-Style-Guide#image-file-format
this is a limitation of mobile GPUs.

Check all PNGs, JPEGs and WebPs against this limit using a small Python
program using Pillow.

Update the GitHub Actions workflow to check out objects from LFS.

[wjt]

https://github.com/endlessm/threadbare/actions/runs/25969999412/job/76340189768 failed successfully:

check image dimensions...................................................Failed
- hook id: check-image-size
- exit code: 1

assets/first_party/wildlife/butterfly/butterfly_air_loop_red.png: 16896x192 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_air_loop_blue.png: 16896x192 exceeds 4096x4096
scenes/menus/title/components/logos/fannypack_logo.png: 4184x1205 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_flower_loop_2_pink.png: 7040x128 exceeds 4096x4096
scenes/menus/storybook/Textures/book_turn_right.png: 9990x720 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_flower_loop_2_green.png: 7040x128 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_air_loop_green.png: 16896x192 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_flower_loop_2_red.png: 7040x128 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_flower_loop_2_blue.png: 7040x128 exceeds 4096x4096
assets/first_party/logo/threadbare-logo-animation.png: 4608x2304 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_air_loop_pink.png: 16896x192 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_air_loop_orange.png: 16896x192 exceeds 4096x4096
scenes/menus/storybook/Textures/book_turn_left.png: 9990x720 exceeds 4096x4096
assets/first_party/wildlife/butterfly/butterfly_flower_loop_2_orange.png: 7040x128 exceeds 4096x4096

#2206 will address these.

[github-actions]

Play this branch at https://play.threadbare.game/branches/endlessm/wjt/pre-commit-check-for-images-exceeding-4096-4096/.

(This launches the game from the start, not directly at the change(s) in this pull request.)

[wjt]

I merged #2156 and restacked this on #2206 which should make the check green.