Add managed server profiles and account login

docs/porting-to-dotnet.md

@@ -851,7 +851,8 @@ Per §8.2. AppKit port, ScreenCaptureKit per-app audio selection, VoiceOver pari
 build produced.
 
 **Checkpoint (2026-09-16):** `clients/apple/dotnet/VoiceCat.Mac` is a separate .NET 10
-AppKit application that consumes `VoiceCat.Core` directly. It implements guest connection,
+AppKit application that consumes `VoiceCat.Core` directly. It implements guest and account
+connection, validated saved server profiles whose JSON never contains passwords,
 interactive TOFU approval, channel browsing, roster/chat, voice subscription, native
 accessibility labels and default-device microphone/playback. Core Audio capture is resampled
 and converted through `AVAudioConverter` before entering the managed audio engine. Stereo
@@ -860,9 +861,9 @@ not allocate, lock or block. Voice stream lifetime follows subscription, disconn
 channel changes. Current Apple API calls compile warning-free against Microsoft's
 26.4.10259 macOS reference assembly, and a macOS CI job builds the native codec/DSP shim and
 Apple solution. A real macOS device run and listen test remain required. The existing Swift
-app remains the release client until saved servers/accounts, selectable devices, the rest of
-the moderation/settings surface, ScreenCaptureKit, VoiceOver validation, signing and
-notarization are complete.
+app remains the release client until protected-channel prompts, optional Keychain credentials,
+selectable devices, the rest of the moderation/settings surface, ScreenCaptureKit, VoiceOver
+validation, signing and notarization are complete.
 
 ---