Separate the web runner from eframe and update egui

[white-axe]

Description

This pull request moves the custom web runner used by Luminol back into a self-contained set of files like it was before #70 to make it easier to update egui, removes the custom eframe and egui-wgpu crates and updates egui to 0.32.0 and wgpu to 25.0.2.

Testing

All the functionality that was previously managed by the web runner should still work:

• Mouse buttons and mouse movement
• Key presses on the keyboard, including modifier keys like control or shift
• Typing text into text boxes using the keyboard
• Typing text into text boxes using an input method editor
• The screen reader (this isn't enabled by default, but can be enabled by setting ctx.options_mut(|o| o.screen_reader = true) anywhere and then focusing buttons or labels in the user interface)
• Resizing the browser window
• Zooming the browser window
• Copying and pasting text
• Clicking on links, like the one in the preset visuals section of the preferences window that links to the Luminol GitHub page

Checklist

• Run cargo fmt.
• Run cargo clippy. If applicable, add:
  • --target wasm32-unknown-unknown -Z build-std=std,panic_abort
• Run cargo build --release
• If applicable, run trunk build --release

[white-axe]

I've added egui-modal as a vendored crate so that egui can be updated past 0.30.0. Since egui starting from version 0.32.0 requires rustc 1.85 or later and some of idna's dependencies now require rustc 1.82 or later, I've updated the nightly toolchain used by the builds to 2025-01-04, the first one from after rustc 1.85. The toolchain also needs to be updated in luminol-website or it'll fail to build.

[melody-rs]

Toasts don't seem to respect egui's scaling anymore?

[white-axe]

It was actually the default font size of the toasts changing. I've changed the font size back to the original one.