Unify styles into single root node & support preload sandboxing

[Vendicated]

Unifies and organises all Vencord styles into one central root node. The main motivation behind this is that previously, styles were all over the place and it was easy to accidentally change the order in which they were inserted, which breaks specificity. That issue happened in an earlier version of this PR. Thus I decided to also reorganise.

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Also refactors the preload script to support Electron process sandboxing, which heavily restricts what the preload can access.

This will only be used on Vesktop because the Discord desktop app does not support sandboxing. But once they eventually enable it, we will already be prepared :)

This is needed for Vencord/Vesktop#1206

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Same PR because they are tangentially related (both refactor Vencord css logic to use IPC instead of doing it fully in the preload)

[Vendicated]

Essentially sandboxing makes it so that the preload script is also sandboxed and has similar access to the renderer (plus a few electron apis). So we have to move all file operations and such to the main process via IPC call. That's what this PR does

[Copilot]

Pull request overview

This PR refactors Vencord's CSS management system to unify all styles into a single hierarchical root node and updates the preload script to support Electron process sandboxing for future compatibility.

• Centralizes all Vencord styles under a vencord-root node with three child nodes for core, managed, and user styles to maintain consistent specificity ordering
• Migrates CSS loading from the preload script to IPC handlers in the main process to support sandboxed preload contexts
• Moves classNameFactory utility from @api/Styles to @utils/css with backwards compatibility maintained

Reviewed changes

Copilot reviewed 50 out of 50 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/api/Styles.ts	Introduces new hierarchical style root nodes and initStyles() function, exports deprecated classNameFactory for backwards compatibility
src/utils/css.ts	Adds classNameFactory and classNameToSelector utilities moved from Styles API
src/preload.ts	Refactored to use IPC for CSS loading instead of direct file system access, supporting sandboxed contexts
src/main/ipcMain.ts	Adds IPC handlers for renderer CSS retrieval and file watching, consolidates file watcher initialization
src/main/patcher.ts	Removes initIpc call as watchers now initialize via IPC request
src/shared/IpcEvents.ts	Adds new IPC events for CSS/JS retrieval and removes unused theme upload/delete events
src/VencordNative.ts	Adds stub implementations for removed theme methods, adds renderer CSS and Monaco theme getters
src/Vencord.ts	Updates to use new initStyles() and coreStyleRootNode
src/api/Themes.ts	Updates to append styles to userStyleRootNode instead of document root
src/components/css.ts	Removed file, functionality moved to src/api/Styles.ts
browser/*	Updates browser extension to pass renderer CSS URL via postMessage instead of direct insertion
scripts/build/buildWeb.mjs	Updates userscript to set CSS via global variable instead of direct DOM insertion
src/plugins/*	Updates 20+ plugin files to import classNameFactory from @utils/css instead of @api/Styles
src/components/*	Updates component files to import classNameFactory from @utils/css

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