remove most uses of as any in typescript

- replaced many uses of `as any` with another more specific cast `as T`
- filled in missing typed for items that needed to be typed
  - new runtime code was added where necessary to satisfy the new types with comments
- added missing theme variable "sidebar-active" to the Theme variables
- forms using `react-hook-form` are now typechecked
- changed some instances of `target` into `currentTarget` while removing `as any` assertions

src/context/revoltjs/SyncManager.tsx

@@ -23,11 +23,11 @@ type Props = WithDispatcher & {
 
 var lastValues: { [key in SyncKeys]?: any } = { };
 
-export function mapSync(packet: Sync.UserSettings, revision?: { [key: string]: number }) {
+export function mapSync(packet: Sync.UserSettings, revision?: Record<string, number>) {
     let update: { [key in SyncKeys]?: [ number, SyncData[key] ] } = {};
     for (let key of Object.keys(packet)) {
         let [ timestamp, obj ] = packet[key];
-        if (timestamp < (revision ?? {} as any)[key] ?? 0) {
+        if (timestamp < (revision ?? {})[key] ?? 0) {
             continue;
         }