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.

tests/unit/presentation/components/Scripts/View/Tree/TreeView/UseCurrentTreeNodes.spec.ts

@@ -59,7 +59,7 @@ describe('useCurrentTreeNodes', () => {
 });
 
 function mountWrapperComponent(treeRootRef: Ref<TreeRoot>) {
-  let returnObject: ReturnType<typeof useCurrentTreeNodes>;
+  let returnObject: ReturnType<typeof useCurrentTreeNodes> | undefined;
   const wrapper = shallowMount(
     defineComponent({
       setup() {
@@ -76,6 +76,9 @@ function mountWrapperComponent(treeRootRef: Ref<TreeRoot>) {
       },
     },
   );
+  if (!returnObject) {
+    throw new Error('missing hook result');
+  }
   return {
     wrapper,
     returnObject,