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/shared/Stubs/ScriptCompilerStub.ts

@@ -1,22 +1,27 @@
 import type { ScriptData } from '@/application/collections/';
 import { IScriptCompiler } from '@/application/Parser/Script/Compiler/IScriptCompiler';
 import { IScriptCode } from '@/domain/IScriptCode';
+import { ScriptCodeStub } from './ScriptCodeStub';
 
 export class ScriptCompilerStub implements IScriptCompiler {
-  public compilables = new Map<ScriptData, IScriptCode>();
+  public compilableScripts = new Map<ScriptData, IScriptCode>();
 
   public canCompile(script: ScriptData): boolean {
-    return this.compilables.has(script);
+    return this.compilableScripts.has(script);
   }
 
   public compile(script: ScriptData): IScriptCode {
-    return this.compilables.get(script);
+    const foundCode = this.compilableScripts.get(script);
+    if (foundCode) {
+      return foundCode;
+    }
+    return new ScriptCodeStub();
   }
 
-  public withCompileAbility(script: ScriptData, result?: IScriptCode): ScriptCompilerStub {
-    this.compilables.set(
+  public withCompileAbility(script: ScriptData, result?: IScriptCode): this {
+    this.compilableScripts.set(
       script,
-      result || { execute: `compiled code of ${script.name}`, revert: `compiled revert code of ${script.name}` },
+      result ?? { execute: `compiled code of ${script.name}`, revert: `compiled revert code of ${script.name}` },
     );
     return this;
   }