Convert to TypeScript and ensure strict type safety

[XDGFX]

Overview

Inspired by PR #98 and #99, and with the desire to use Typia functions which means types must be properly defined, I have ported all the JS functions to fully typed TS.

The only function signature change is in src/utils.ts, where the hasOwnProperty method expects a PropertyKey parameter, so I updated the function to expect that type only.
No other function signatures are changed.

The benefit is that for all functions, TS users have a reliable type output based on the types supplied as inputs. No change to JS users.

Ensured that build, lint, test, and test:coverage all pass without errors. Replaced yarn commands with npm as yarn was not specified as a devDependency.

Types

The main types returned by the various diff functions are now defined as follows:

export type DiffDeletedType<T, U> =
    | {
          [P in Exclude<keyof ElementType<T>, keyof ElementType<U>>]: undefined;
      }
    | EmptyObject;

export type DiffAddedType<T, U> =
    | {
          [P in Exclude<
              keyof ElementType<U>,
              keyof ElementType<T>
          >]: ElementType<U>[P];
      }
    | EmptyObject;

export type DiffUpdatedType<T, U> =
    | {
          [P in keyof ElementType<T> & keyof ElementType<U>]?: DiffUpdatedType<
              ElementType<T>[P],
              ElementType<U>[P]
          >;
      }
    | U
    | EmptyObject;

export type DiffType<T, U> =
    | U
    | (DiffAddedType<T, U> & DiffDeletedType<T, U> & DiffUpdatedType<T, U>);

The types were determined by reading the function code and ensuring the returned values match the specified type.