feat(ui): mesh header "Flash LoRa" button opens the in-app flash flow

Replaces the external flasher.meshcore.co.uk link with a button that
opens the global device-setup modal directly at its flash step, via a
new manual entry point in the mesh store (flashFlowPath). Manual opens
target the connected radio (else the first detected stick), skip the
read-only probe — the port is held by the live session and a second tty
opener corrupts it; the backend flash job stops the listener itself —
and close the modal instead of stepping back to the detection screen.
Button is disabled with a hint when no radio is present.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/stores/mesh.ts

@@ -377,6 +377,16 @@ export const useMeshStore = defineStore('mesh', () => {
     }
     localStorage.setItem(DETECT_DISMISS_KEY, JSON.stringify(dismissedDetected.value))
   }
+  // Manual "Flash LoRa" entry (Mesh header button): forces the global setup
+  // modal open at the flash step for this port — including the live session's
+  // port, which detection-driven opening deliberately excludes.
+  const flashFlowPath = ref<string | null>(null)
+  function openFlashFlow(path: string) {
+    flashFlowPath.value = path
+  }
+  function closeFlashFlow() {
+    flashFlowPath.value = null
+  }
   /** Read-only firmware/config probe of a detected port (hot-swap modal). */
   async function probeDevice(path: string): Promise<MeshDeviceProbe> {
     return rpcClient.call<MeshDeviceProbe>({
@@ -1066,6 +1076,9 @@ export const useMeshStore = defineStore('mesh', () => {
     fetchStatus,
     undismissedDetectedDevices,
     dismissDetectedDevice,
+    flashFlowPath,
+    openFlashFlow,
+    closeFlashFlow,
     probeDevice,
     flashListFirmware,
     flashDevice,