Refactor to enforce strictNullChecks

This commit applies `strictNullChecks` to the entire codebase to improve
maintainability and type safety. Key changes include:

- Remove some explicit null-checks where unnecessary.
- Add necessary null-checks.
- Refactor static factory functions for a more functional approach.
- Improve some test names and contexts for better debugging.
- Add unit tests for any additional logic introduced.
- Refactor `createPositionFromRegexFullMatch` to its own function as the
  logic is reused.
- Prefer `find` prefix on functions that may return `undefined` and
  `get` prefix for those that always return a value.

src/infrastructure/RuntimeSanity/Common/FactoryValidator.ts

@@ -7,9 +7,6 @@ export abstract class FactoryValidator<T> implements ISanityValidator {
   private readonly factory: FactoryFunction<T>;
 
   protected constructor(factory: FactoryFunction<T>) {
-    if (!factory) {
-      throw new Error('missing factory');
-    }
     this.factory = factory;
   }
 

src/infrastructure/RuntimeSanity/SanityChecks.ts

@@ -11,7 +11,9 @@ export function validateRuntimeSanity(
   options: ISanityCheckOptions,
   validators: readonly ISanityValidator[] = DefaultSanityValidators,
 ): void {
-  validateContext(options, validators);
+  if (!validators.length) {
+    throw new Error('missing validators');
+  }
   const errorMessages = validators.reduce((errors, validator) => {
     if (validator.shouldValidate(options)) {
       const errorMessage = getErrorMessage(validator);
@@ -26,21 +28,6 @@ export function validateRuntimeSanity(
   }
 }
 
-function validateContext(
-  options: ISanityCheckOptions,
-  validators: readonly ISanityValidator[],
-) {
-  if (!options) {
-    throw new Error('missing options');
-  }
-  if (!validators?.length) {
-    throw new Error('missing validators');
-  }
-  if (validators.some((validator) => !validator)) {
-    throw new Error('missing validator in validators');
-  }
-}
-
 function getErrorMessage(validator: ISanityValidator): string | undefined {
   const errorMessages = [...validator.collectErrors()];
   if (!errorMessages.length) {