Standardize file naming and improve typings export

Renamed functions files to follow consistent camelCase convention. Added a missing type export for ITSInjex interface in the main index file, enabling better TypeScript type support and ensuring interfaces are available for external modules.

src/functions/resolve.ts

@@ -0,0 +1,33 @@
+import { DependencyResolutionError } from '../interfaces/Exceptions';
+import { TSInjex } from '../TSInjex';
+
+/**
+ * Resolve a dependency.
+ * @param identifier The identifier of the dependency.
+ * @returns The resolved dependency.
+ * @throws A {@link DependencyResolutionError} if the dependency is not found.
+ */
+export function resolve<T>(identifier: string): T;
+
+/**
+ * Resolve a dependency
+ * @param identifier The identifier of the dependency.
+ * @param necessary The dependency is **not** necessary.
+ * @returns The resolved dependency or undefined if the dependency is not found.
+ */
+export function resolve<T>(identifier: string, necessary: false): T | undefined;
+
+/**
+ * Resolve a dependency.
+ * @param identifier The identifier of the dependency.
+ * @param necessary If true, throws an error if the dependency is not found.
+ * @returns The resolved dependency or undefined if the dependency is not necessary
+ * and not found, or throws an error if the dependency is necessary and not found.
+ * @throws A {@link DependencyResolutionError} if the dependency is not found and necessary.
+ */
+export function resolve<T>(
+    identifier: string,
+    necessary?: boolean,
+): T | undefined {
+    return TSInjex.getInstance().resolve<T>(identifier, necessary);
+}