Refactor text utilities and expand their usage

This commit refactors existing text utility functions into the
application layer for broad reuse and integrates them across
the codebase. Initially, these utilities were confined to test
code, which limited their application.

Changes:

- Move text utilities to the application layer.
- Centralize text utilities into dedicated files for better
  maintainability.
- Improve robustness of utility functions with added type checks.
- Replace duplicated logic with centralized utility functions
  throughout the codebase.
- Expand unit tests to cover refactored code parts.

tests/unit/application/Common/Text/SplitTextIntoLines.spec.ts

@@ -0,0 +1,96 @@
+import { describe, it, expect } from 'vitest';
+import { splitTextIntoLines } from '@/application/Common/Text/SplitTextIntoLines';
+import type { isString } from '@/TypeHelpers';
+import { IsStringStub } from '@tests/unit/shared/Stubs/IsStringStub';
+
+describe('splitTextIntoLines', () => {
+  describe('splits correctly', () => {
+    // arrange
+    const testScenarios: readonly {
+      readonly description: string;
+      readonly text: string;
+      readonly expectedLines: readonly string[];
+    } [] = [
+      {
+        description: 'handles Unix-like line separator',
+        text: 'Hello\nWorld\nTest',
+        expectedLines: ['Hello', 'World', 'Test'],
+      },
+      {
+        description: 'handles Windows line separator',
+        text: 'Hello\r\nWorld\r\nTest',
+        expectedLines: ['Hello', 'World', 'Test'],
+      },
+      {
+        description: 'handles mixed indentation (both Unix-like and Windows)',
+        text: 'Hello\r\nWorld\nTest',
+        expectedLines: ['Hello', 'World', 'Test'],
+      },
+      {
+        description: 'returns an array with one element when no new lines',
+        text: 'Hello World',
+        expectedLines: ['Hello World'],
+      },
+      {
+        description: 'preserves empty lines between text lines',
+        text: 'Hello\n\nWorld\n\n\nTest\n',
+        expectedLines: ['Hello', '', 'World', '', '', 'Test', ''],
+      },
+      {
+        description: 'handles empty strings',
+        text: '',
+        expectedLines: [''],
+      },
+    ];
+    testScenarios.forEach(({
+      description, text, expectedLines,
+    }) => {
+      it(description, () => {
+        const testContext = new TestContext()
+          .withText(text);
+        // act
+        const result = testContext.splitText();
+        // assert
+        expect(result).to.deep.equal(expectedLines);
+      });
+    });
+  });
+  it('checks for string type', () => {
+    // arrange
+    const invalidInput = 42;
+    const errorMessage = `Line splitting error: Expected a string but received type '${typeof invalidInput}'.`;
+    const isString = new IsStringStub()
+      .withPredeterminedResult(false)
+      .get();
+    // act
+    const act = () => new TestContext()
+      .withText(invalidInput as unknown as string)
+      .withIsStringType(isString)
+      .splitText();
+    // assert
+    expect(act).to.throw(errorMessage);
+  });
+});
+
+class TestContext {
+  private isStringType: typeof isString = new IsStringStub().get();
+
+  private text: string = `[${TestContext.name}] text value`;
+
+  public withText(text: string): this {
+    this.text = text;
+    return this;
+  }
+
+  public withIsStringType(isStringType: typeof isString): this {
+    this.isStringType = isStringType;
+    return this;
+  }
+
+  public splitText(): ReturnType<typeof splitTextIntoLines> {
+    return splitTextIntoLines(
+      this.text,
+      this.isStringType,
+    );
+  }
+}