feat: Implement module-specific accent colors and enhance theme integration

This commit introduces module-specific accent colors and further integrates
the primary and secondary theme colors throughout the application's UI components.

Key features:
- Four new customizable accent colors, one for each main module:
    - Empleados
    - Tareas
    - Planillas
    - Asistencias
- These accent colors are configurable in the Settings view and persist in local storage.
- Broader application of global primary and secondary colors to common UI elements like navigation bars.
- Module-specific components now use their designated accent color for key visual elements (e.g., primary buttons, titles, icons, borders), providing better visual differentiation between modules.

Changes include:
- Extended `ui/src/stores/useUi.js` to manage state for the four new module accent colors, including actions and local storage persistence.
- Added a "Module Accent Colors" section with color pickers to `ui/src/views/SettingsView.vue`.
- Updated `ui/src/App.vue` to expose these module accent colors as CSS variables (e.g., `--accent-color-empleados`).
- Systematically updated styles in general UI components (`ui/src/components/ui/`) and all module-specific components (`ui/src/components/{module}/` and `ui/src/views/{module}/`) to utilize the new global and module-specific theme colors.
- Updated unit tests for `useUi.js` and component tests for `SettingsView.vue` to cover the new accent color functionality. A bug related to color input event handling in `SettingsView.vue` was identified and fixed during this process.

This enhancement provides a more visually distinct and customizable experience across different sections of the application.

ui/src/views/asistencias/AsistenciasIndex.vue

@@ -89,26 +89,26 @@ const handleEditAsistencia = (asistenciaId) => {
 }
 
 .page-header h1 {
-  color: #212529; 
+  color: var(--accent-color-asistencias); /* Accent color for title */
   font-size: 1.8em; 
   font-weight: 600;
 }
 
 .btn-create {
-  background-color: #17a2b8; /* Info Blue */
-  color: white;
+  background-color: var(--accent-color-asistencias);
+  color: white; /* Assuming accent is dark enough */
   padding: 10px 18px; 
   border: none;
   border-radius: 5px;
   font-size: 1em;
   font-weight: 500;
   cursor: pointer;
-  transition: background-color 0.2s ease-in-out, box-shadow 0.2s ease;
+  transition: background-color 0.2s ease-in-out, box-shadow 0.2s ease, filter 0.2s ease;
   box-shadow: 0 2px 5px rgba(0,0,0,0.1);
 }
 
 .btn-create:hover {
-  background-color: #138496; 
+  filter: brightness(0.9);
   box-shadow: 0 4px 8px rgba(0,0,0,0.15);
 }