Service: drop the WASAPI inputs (mic) list — outputs and apps only

The service streams a machine's OUTPUT audio (or specific apps); capturing a mic from an
unattended, logged-out box isn't a use case (Ed). Removed the "WASAPI audio inputs to
send" list from the service config dialog, and made the service ignore inputs everywhere:

- ServiceProfileDialog: removed the inputs CheckedListBox, its status label, its row and
  accessibility wiring. Save now clears SelectedWasapiSendInputs so a profile saved by an
  older build can't keep a mic streaming.
- ServiceSendHost.BuildSendSpecs: removed the input-spec loop — a legacy profile's inputs
  are deliberately ignored.

(The main app is unchanged: it still has its WASAPI inputs list and AudioDeviceCatalog
.LoadInputs stays for it.)

Test: the service-parity test now adds a mic to the profile and asserts BuildSendSpecs
emits only per-application specs and never a CaptureKind.Input. Gate 46/46.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/RemSound.App/SelfTest.cs

@@ -1000,11 +1000,14 @@ internal static class SelfTest
         {
             var appsProfile = new Profile { WasapiSendMode = "applications", SendAllApplications = true };
             appsProfile.SelectedSendApplications.Add("nonexistent-proc-for-test");
+            appsProfile.SelectedWasapiSendInputs.Add("some-mic-id");   // legacy input selection must be ignored
             var appSpecs = ServiceSendHost.BuildSendSpecs(appsProfile);
             Check(!appSpecs.Any(s => s.Kind == CaptureKind.Loopback),
                 "applications mode must NOT produce a whole-system loopback spec, even with SendAllApplications=true");
-            Check(appSpecs.All(s => s.Kind is CaptureKind.ProcessLoopback or CaptureKind.Input),
-                "applications mode must build only per-application (or input) specs — the 'send all' path is gone");
+            Check(appSpecs.All(s => s.Kind == CaptureKind.ProcessLoopback),
+                "the service builds only per-application specs — no whole-system loopback, and no WASAPI inputs");
+            Check(!appSpecs.Any(s => s.Kind == CaptureKind.Input),
+                "the service must never send WASAPI inputs, even if a legacy profile still lists one");
         }
         return "service forces Opus + 2.5ms frame + lock-to-clock; apps mode is specific-apps-only; crypto matches";
     }