feat(z-task-modal): improve employee selection logic and add weekend overlay in timeblock components

app/src/plugins/tm@modal/task/z-task-modal.vue

@@ -531,19 +531,20 @@ export default {
       const employeeId = itemObject.value;
 
       if (!this.subtask.id) {
-        // New subtask with multiple employees support or edit of draft with multiple employees
-        return (
-          shouldShowItem &&
-          !this.timeblocks.some((tb) => tb.employee_id === employeeId)
+        // New subtask with multiple employees support
+        // Hide employees that are already selected in any slot
+        // The v-autocomplete will still display the currently selected employee
+        const isAlreadySelected = this.subtask.employees.some(
+          (emp) => emp.id && Number(emp.id) === employeeId,
         );
+        return shouldShowItem && !isAlreadySelected;
       } else if (this.subtask.is_draft) {
         // Edit draft subtask with multiple employees support
-        return (
-          shouldShowItem &&
-          !this.subtask.employees.some(
-            (employee) => Number(employee.id) === employeeId,
-          )
+        // Hide employees that are already selected in any slot
+        const isAlreadySelected = this.subtask.employees.some(
+          (emp) => emp.id && Number(emp.id) === employeeId,
         );
+        return shouldShowItem && !isAlreadySelected;
       } else {
         // Saved standard subtask, allow "re-select" for better UX
         return shouldShowItem;
@@ -1046,8 +1047,9 @@ export default {
 
           // For drafts with multiple employees, include employees array
           if (this.subtask.is_draft && this.isDraftWithMultipleEmployees) {
-            const validEmployees = this.subtask.employees.filter(
-              (employee) => employee.id && employee.duration,
+            const validEmployees = this._filterValidEmployees(
+              this.subtask.employees,
+              concept,
             );
 
             // Assign timeblocks to each employee
@@ -1090,9 +1092,9 @@ export default {
           this.$store.commit('tm/update_subtask', subtask);
           this.$events.emit('on-subtask-edited', this.subtask);
         } else {
-          // Filter out employees that don't have both id and duration
-          const validEmployees = this.subtask.employees.filter(
-            (employee) => employee.id && employee.duration,
+          const validEmployees = this._filterValidEmployees(
+            this.subtask.employees,
+            concept,
           );
 
           // Assign timeblocks to each employee based on employee_id
@@ -1198,6 +1200,18 @@ export default {
       }
     },
 
+    _filterValidEmployees(employees, isConcept) {
+      // Filter employees based on whether it's a concept/draft or published task
+      // For concepts: only require id (duration can be null/0)
+      // For published tasks: require both id and duration
+      return employees.filter((employee) => {
+        if (isConcept) {
+          return employee.id; // Only require ID for concepts/drafts
+        }
+        return employee.id && employee.duration; // Require both for published tasks
+      });
+    },
+
     async _validateEmployees() {
       if (this.subtask.id && !this.subtask.is_draft) {
         // For existing subtasks, at least one employee is required