Add clear DTC codes button to Pi DTC page (FEAT-15)

templates/dtc.html

@@ -14,6 +14,9 @@
         <button id="dtc-refresh-btn" class="btn btn-sm btn-secondary">
             <i class="fas fa-sync-alt me-1"></i>Refresh
         </button>
+        <button id="dtc-clear-btn" class="btn btn-sm btn-outline-danger">
+            <i class="fas fa-eraser me-1"></i>Clear codes
+        </button>
     </div>
 </div>
 
@@ -42,6 +45,7 @@
     const milEl = document.getElementById('mil-indicator');
     const updatedEl = document.getElementById('dtc-updated');
     const refreshBtn = document.getElementById('dtc-refresh-btn');
+    const clearBtn = document.getElementById('dtc-clear-btn');
     const body = document.querySelector('#dtc-list [data-data-list-body]');
 
     async function loadDtc() {
@@ -83,6 +87,29 @@
     }
 
     refreshBtn.addEventListener('click', loadDtc);
+
+    clearBtn.addEventListener('click', async function () {
+        if (!window.confirm('Clear all DTC codes from the car ECU? This clears the check-engine light unless a fault is still present.')) {
+            return;
+        }
+        clearBtn.disabled = true;
+        updatedEl.textContent = 'Clearing…';
+        try {
+            const r = await fetch('/api/dtc/clear', { method: 'POST' });
+            const d = await r.json();
+            if (!r.ok) {
+                updatedEl.textContent = d.error || 'Clear failed';
+                return;
+            }
+            await loadDtc();
+            updatedEl.textContent = 'Codes cleared';
+        } catch (e) {
+            updatedEl.textContent = 'Clear failed';
+        } finally {
+            clearBtn.disabled = false;
+        }
+    });
+
     loadDtc();
 })();
 </script>