fix(apple): latency HUD — interpolate the (same-host) suffix, don't concat

The capture->client latency line concatenated a String onto a LocalizedStringKey
(Text("...\(x, specifier:)..." + (cond ? "" : "...")), which doesn't type-check:
the specifier: interpolation makes the literal a LocalizedStringKey, which has no
'+'. Fold the conditional suffix into the interpolation instead — the Apple
client didn't build on the latency-HUD commit (e04328f).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/apple/Sources/PunktfunkClient/ContentView.swift

@@ -631,8 +631,7 @@ struct ContentView: View {
             if model.latencyValid {
                 // Capture→client-receipt (skew-corrected); excludes the layer's decode+present —
                 // see LatencyMeter. "(same-host)" when the host didn't answer the skew handshake.
-                Text("capture→client \(model.latencyP50Ms, specifier: "%.1f")/\(model.latencyP95Ms, specifier: "%.1f") ms p50/p95"
-                    + (model.latencySkewCorrected ? "" : " (same-host)"))
+                Text("capture→client \(model.latencyP50Ms, specifier: "%.1f")/\(model.latencyP95Ms, specifier: "%.1f") ms p50/p95\(model.latencySkewCorrected ? "" : " (same-host)")")
                     .font(.system(.caption2, design: .monospaced))
                     .foregroundStyle(.secondary)
             }