Improve script error dialogs #304

- Include the script's directory path #304.
- Exclude Windows-specific instructions on non-Windows OS.
- Standardize language across dialogs for consistency.

Other supporting changes:

- Add script diagnostics data collection from main process.
- Document script file storage and execution tamper protection in
  SECURITY.md.
- Remove redundant comment in `NodeReadbackFileWriter`.
- Centralize error display for uniformity and simplicity.
- Simpify `WindowVariablesValidator` to omit checks when not on the
  renderer process.
- Improve and centralize Electron environment detection.
- Use more emphatic language (don't worry) in error messages.

tests/unit/shared/Stubs/ScriptDiagnosticsCollectorStub.ts

@@ -0,0 +1,25 @@
+import { ScriptDiagnosticData, ScriptDiagnosticsCollector } from '@/application/ScriptDiagnostics/ScriptDiagnosticsCollector';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+
+export class ScriptDiagnosticsCollectorStub implements ScriptDiagnosticsCollector {
+  private operatingSystem: OperatingSystem | undefined = OperatingSystem.Windows;
+
+  private scriptDirectoryPath: string | undefined = '/test/scripts/directory/path';
+
+  public withOperatingSystem(operatingSystem: OperatingSystem | undefined): this {
+    this.operatingSystem = operatingSystem;
+    return this;
+  }
+
+  public withScriptDirectoryPath(scriptDirectoryPath: string | undefined): this {
+    this.scriptDirectoryPath = scriptDirectoryPath;
+    return this;
+  }
+
+  public collectDiagnosticInformation(): Promise<ScriptDiagnosticData> {
+    return Promise.resolve({
+      scriptsDirectoryAbsolutePath: this.scriptDirectoryPath,
+      currentOperatingSystem: this.operatingSystem,
+    });
+  }
+}