Stricter TypeScript

[WarningImHack3r]

Make TypeScript even stricter. Here are the changes:

• Use @total-typescript/ts-reset and import it in src/reset.d.ts (I guess every src/**/*.d.ts is imported by default). Click on it to see all its benefits.
• Set the noUncheckedIndexedAccess rule to true in tsconfig.json to make TS consider the following:

   const a = ["a", "b", "c"];
   const b = a[1]; // Now typed `string | undefined` instead of `string`

There might be some other rules to enable/set by making a tour of all the tsconfig rules but I guess we're fine like this.