fix backspace needing double input on wasm

* add TODOs

* separate CosmicEdit from display

breaks loads of stuff: sizing, click functions, cursor hovering just a few

Only tested on login example

not optimized; spams handle weak clones to ensure got correct handle (will be fixed by new handle swapping routine)

not sure about the API changes but might just need to get used to it, is much more extensible

* break render function apart

centered padding now broken, not tested other text positions

* reshape earlier in render to fix padding issue

* move image creation to own system

* resize internal sprite to computed UI size

* prevent panic on zero size UI elements

* clicks + editor-display one-to-many relationships

* add render systemset

* fix hoverable invisible sprites

* update examples

* fix auto-height bugs

* clippy

* rework placeholders to use single editor

* add default placeholder color

* move placeholder systems out of main render

* explicit ordering for password/placeholder systems

basic password implementation

unicode chars are buggy in this commit

i do not like the online merge conflict editor

`CosmicMetrics` default scale to window scale

adds bullet (U+2022) to font subset

replaces rendered text with bullets in password fields

- selection in password widgets is buggy

simplify bundles; use bevy's ButtonBundle and SpriteBundle for layout. Use CosmicCanvas(Handle<Image>) for rendering.

adds a `CosmicCanvas` component to hold the image cosmic draws to. allows easier interop between UI and Sprite widgets

Each type of widget now uses a single `CosmicEditBundle`, adding widget specific components with `.insert()` or as tuples.

fix transparent backgrounds with opaque text

refactor + move rendering fns to own file

Merged redraw and redraw_ui into a single function, in order to make placeholder and password code easier

Moved most of redraw_common into main redraw function, having type wrangling issues with the image replace function

* implement copy/paste for wasm

* ignore wasm specific "dead" code

* fix ctrl instead of command on mac

* fix character input if clipboard shortcut held

* extract undo redo to own fn and refac

* fix first edit not being undoable

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Co-authored-by: StaffEngineer <111751109+StaffEngineer@users.noreply.github.com>