Add find-me LED locate on master and slaves via ESP-NOW.

UART FIND_ME (client_id 0 = local ring, >0 = unicast), ESPNOW_FIND_ME payload, CLI/dashboard buttons per slave.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/webui/index.html

@@ -227,6 +227,12 @@
                         :disabled="busy || !state.uart_connected">
                   Setzen
                 </button>
+                <button type="button" class="btn btn-outline-warning btn-sm"
+                        @click="findMe()"
+                        :disabled="busy || !state.uart_connected"
+                        title="LED-Ring: Rot/Grün/Blau je 3×">
+                  Find me
+                </button>
               </div>
               <p class="text-muted small mt-2 mb-0" x-show="!state.uart_connected">
                 UART nicht verbunden — Eingabe gesperrt.
@@ -300,6 +306,12 @@
                                   title="ESP-NOW Unicast-Test">
                             Test
                           </button>
+                          <button type="button" class="btn btn-outline-warning btn-sm"
+                                  @click="findMe(c.id)"
+                                  :disabled="busy || !state.uart_connected || !c.available"
+                                  title="LED-Ring Find me (ESP-NOW)">
+                            Find me
+                          </button>
                         </div>
                       </td>
                     </tr>
@@ -726,6 +738,27 @@
           } finally {
             this.busy = false;
           }
+        },
+        async findMe(clientId = 0) {
+          this.busy = true;
+          try {
+            const r = await fetch('/api/find-me', {
+              method: 'POST',
+              headers: { 'Content-Type': 'application/json' },
+              body: JSON.stringify({ client_id: clientId })
+            });
+            const data = await r.json();
+            if (!r.ok || !data.success) {
+              this.flash(data.error || 'Find me fehlgeschlagen', false);
+              return;
+            }
+            const label = clientId === 0 ? 'Master' : `Slave ${clientId}`;
+            this.flash(`Find me gestartet (${label})`, true);
+          } catch (e) {
+            this.flash(String(e), false);
+          } finally {
+            this.busy = false;
+          }
         }
       };
     }