Fix Add Adjustment form silently failing — add validation + required fields

Root cause: V5 was missing required attributes that V2 had on the Add
Adjustment form. When a user submitted without selecting a project (for
types that require one), the server rejected it with messages.error()
but the error was invisible before the MESSAGE_TAGS fix. Combined with
no client-side validation for workers, the form would silently create
0 adjustments or redirect with no visible feedback.

Fixes:
- Add required attribute to Project select (toggles off for Loan types)
- Add client-side validation: blocks submit if no workers selected
- Add backend validation: returns error if no workers in POST data
- Add "Select All" / "Clear" links for worker checkboxes (matches V2)
- Add "X worker(s) selected" counter for visual feedback

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/templates/core/payroll_dashboard.html

@@ -382,10 +382,10 @@
                             </select>
                         </div>
 
-                        {# Project #}
+                        {# Project — required for most types, hidden for Loan types #}
                         <div class="col-md-6" id="addAdjProjectGroup">
                             <label class="form-label">Project</label>
-                            <select name="project" class="form-select" id="addAdjProject">
+                            <select name="project" class="form-select" id="addAdjProject" required>
                                 <option value="">-- Select Project --</option>
                                 {% for p in active_projects %}
                                 <option value="{{ p.id }}">{{ p.name }}</option>
@@ -408,13 +408,15 @@
                         {# Workers - multi-select with team helper #}
                         <div class="col-12">
                             <label class="form-label">Workers</label>
-                            <div class="mb-2">
+                            <div class="mb-2 d-flex flex-wrap gap-2 align-items-center">
                                 <select id="addAdjTeamSelect" class="form-select form-select-sm" style="max-width: 250px;">
                                     <option value="">Quick select by team...</option>
                                     {% for team in all_teams %}
                                     <option value="{{ team.id }}">{{ team.name }}</option>
                                     {% endfor %}
                                 </select>
+                                <a href="#" id="adjSelectAll" class="small text-primary text-decoration-none text-nowrap">Select All</a>
+                                <a href="#" id="adjDeselectAll" class="small text-muted text-decoration-none text-nowrap">Clear</a>
                             </div>
                             <div style="max-height: 200px; overflow-y: auto; border: 1px solid #dee2e6; border-radius: 4px; padding: 8px;">
                                 {% for w in all_workers %}
@@ -425,6 +427,13 @@
                                 </div>
                                 {% endfor %}
                             </div>
+                            {# Counter + validation message for workers #}
+                            <div class="form-text mt-1">
+                                <span id="adjSelectedCount">0</span> worker(s) selected
+                            </div>
+                            <div class="invalid-feedback" id="addAdjWorkerError" style="display: none;">
+                                Please select at least one worker.
+                            </div>
                         </div>
 
                         {# Description #}
@@ -906,35 +915,108 @@ document.addEventListener('DOMContentLoaded', function() {
     }
 
     // =================================================================
-    // ADD ADJUSTMENT — Team quick-select + project visibility
+    // ADD ADJUSTMENT — Team quick-select, project visibility,
+    // worker count display, and form validation
     // =================================================================
     const addAdjType = document.getElementById('addAdjType');
     const addAdjProjectGroup = document.getElementById('addAdjProjectGroup');
+    const addAdjProject = document.getElementById('addAdjProject');
     const addAdjTeamSelect = document.getElementById('addAdjTeamSelect');
+    const addAdjWorkerCheckboxes = document.querySelectorAll('.add-adj-worker');
+    const adjSelectedCount = document.getElementById('adjSelectedCount');
+    const addAdjWorkerError = document.getElementById('addAdjWorkerError');
 
-    // Show/hide project field based on adjustment type
+    // Show/hide project field based on adjustment type.
+    // Also toggles the HTML "required" attribute so browser validation
+    // only enforces the project when the type actually needs one.
     function toggleProjectField() {
         if (!addAdjType || !addAdjProjectGroup) return;
         // Loan and Loan Repayment don't need a project
-        const noProjectTypes = ['New Loan', 'Loan Repayment'];
+        var noProjectTypes = ['New Loan', 'Loan Repayment'];
-        addAdjProjectGroup.style.display = noProjectTypes.indexOf(addAdjType.value) !== -1 ? 'none' : '';
+        var needsProject = noProjectTypes.indexOf(addAdjType.value) === -1;
+        addAdjProjectGroup.style.display = needsProject ? '' : 'none';
+        if (addAdjProject) {
+            if (needsProject) {
+                addAdjProject.setAttribute('required', '');
+            } else {
+                addAdjProject.removeAttribute('required');
+                addAdjProject.value = '';  // Clear selection when hidden
+            }
+        }
     }
     if (addAdjType) {
         addAdjType.addEventListener('change', toggleProjectField);
         toggleProjectField();
     }
 
+    // Update the "X worker(s) selected" counter
+    function updateWorkerCount() {
+        var count = 0;
+        addAdjWorkerCheckboxes.forEach(function(cb) {
+            if (cb.checked) count++;
+        });
+        if (adjSelectedCount) adjSelectedCount.textContent = count;
+        // Hide the error message when workers are selected
+        if (addAdjWorkerError && count > 0) {
+            addAdjWorkerError.style.display = 'none';
+        }
+    }
+    addAdjWorkerCheckboxes.forEach(function(cb) {
+        cb.addEventListener('change', updateWorkerCount);
+    });
+
+    // Select All / Deselect All links
+    var adjSelectAllLink = document.getElementById('adjSelectAll');
+    var adjDeselectAllLink = document.getElementById('adjDeselectAll');
+    if (adjSelectAllLink) {
+        adjSelectAllLink.addEventListener('click', function(e) {
+            e.preventDefault();
+            addAdjWorkerCheckboxes.forEach(function(cb) { cb.checked = true; });
+            updateWorkerCount();
+        });
+    }
+    if (adjDeselectAllLink) {
+        adjDeselectAllLink.addEventListener('click', function(e) {
+            e.preventDefault();
+            addAdjWorkerCheckboxes.forEach(function(cb) { cb.checked = false; });
+            updateWorkerCount();
+        });
+    }
+
     // Team quick-select: check workers in that team
     if (addAdjTeamSelect) {
         addAdjTeamSelect.addEventListener('change', function() {
-            const teamId = this.value;
+            var teamId = this.value;
             if (!teamId) return;
-            const workerIds = teamWorkersMap[teamId] || [];
+            var workerIds = teamWorkersMap[teamId] || [];
-            document.querySelectorAll('.add-adj-worker').forEach(function(cb) {
+            addAdjWorkerCheckboxes.forEach(function(cb) {
                 if (workerIds.indexOf(parseInt(cb.value)) !== -1) {
                     cb.checked = true;
                 }
             });
+            updateWorkerCount();
+        });
+    }
+
+    // Form validation: ensure at least one worker is selected before submit.
+    // Without this, the form would submit and silently create 0 adjustments.
+    var addAdjForm = document.querySelector('#addAdjustmentModal form');
+    if (addAdjForm) {
+        addAdjForm.addEventListener('submit', function(e) {
+            var anyChecked = false;
+            addAdjWorkerCheckboxes.forEach(function(cb) {
+                if (cb.checked) anyChecked = true;
+            });
+            if (!anyChecked) {
+                e.preventDefault();
+                if (addAdjWorkerError) {
+                    addAdjWorkerError.style.display = 'block';
+                }
+                // Scroll to the workers section so the error is visible
+                var workersLabel = addAdjForm.querySelector('.col-12');
+                if (workersLabel) workersLabel.scrollIntoView({behavior: 'smooth', block: 'center'});
+                return false;
+            }
         });
     }
 

core/views.py

@@ -1100,6 +1100,13 @@ def add_adjustment(request):
     date_str = request.POST.get('date', '')
     project_id = request.POST.get('project', '')
 
+    # Validate workers — at least one must be selected.
+    # The frontend also checks this, but this is a safety net in case
+    # the user has JavaScript disabled or submits via other means.
+    if not worker_ids:
+        messages.error(request, 'Please select at least one worker.')
+        return redirect('payroll_dashboard')
+
     # Validate amount
     try:
         amount = Decimal(amount_str)