feat: Super Check Partial + N+1 helper; fix Flex binding to SmartSDR CAT; telemetry callsign wait

- SCP/N+1: new internal/scp downloads the community MASTER.SCP master list and a
  docked two-column widget shows, as you type a call, the known calls containing it
  (Partial) and the calls one edit away (N+1) — click to fix a busted call. Opt-in
  in Settings → General; top-bar toggle; queried debounced on callsign input.
- Flex: OpsLog's GUI-client detection was too loose and could bind to "SmartSDR CAT"
  (or DAX) — both carry "smartsdr" in the program name — instead of the real GUI
  client, making SmartSDR CAT drop and reconnect in a loop while OpsLog was open.
  Now it binds only to a real SmartSDR/Maestro GUI client (e.g. a FLEX-8600M's
  integrated screen) and excludes cat/dax; dropped the risky empty-program fallback.
- Telemetry: on a fresh install the callsign isn't set at launch, so the once-a-day
  heartbeat recorded the machine UUID. Now it waits (~10 min) for the operator to
  enter their callsign before sending, falling back to the UUID only if none appears.

frontend/wailsjs/go/main/App.js

@@ -298,6 +298,10 @@ export function DownloadLoTWUsers() {
   return window['go']['main']['App']['DownloadLoTWUsers']();
 }
 
+export function DownloadScp() {
+  return window['go']['main']['App']['DownloadScp']();
+}
+
 export function DownloadULSCounties() {
   return window['go']['main']['App']['DownloadULSCounties']();
 }
@@ -870,6 +874,10 @@ export function GetSPEStatus() {
   return window['go']['main']['App']['GetSPEStatus']();
 }
 
+export function GetScpStatus() {
+  return window['go']['main']['App']['GetScpStatus']();
+}
+
 export function GetSecretStatus() {
   return window['go']['main']['App']['GetSecretStatus']();
 }
@@ -1662,6 +1670,10 @@ export function SaveWinkeyerSettings(arg1) {
   return window['go']['main']['App']['SaveWinkeyerSettings'](arg1);
 }
 
+export function ScpLookup(arg1) {
+  return window['go']['main']['App']['ScpLookup'](arg1);
+}
+
 export function SearchAwardReferences(arg1, arg2, arg3, arg4) {
   return window['go']['main']['App']['SearchAwardReferences'](arg1, arg2, arg3, arg4);
 }
@@ -1730,6 +1742,10 @@ export function SetPassphrase(arg1) {
   return window['go']['main']['App']['SetPassphrase'](arg1);
 }
 
+export function SetScpEnabled(arg1) {
+  return window['go']['main']['App']['SetScpEnabled'](arg1);
+}
+
 export function SetTelemetryEnabled(arg1) {
   return window['go']['main']['App']['SetTelemetryEnabled'](arg1);
 }