Add priority mode + always-on network packet priority

Priority mode (per-profile toggle, Audio profile tab, Alt+U):
- Bundled PROCESS_POWER_THROTTLING_STATE with EXECUTION_SPEED and
  IGNORE_TIMER_RESOLUTION flags (keeps CPU at full clock + 1 ms quantum
  pinned regardless of OS idle decisions)
- PowerSetRequest(EXECUTION_REQUIRED) + SetThreadExecutionState so the
  system can't decide we're idle and downclock
- timeBeginPeriod(1) for 1 ms scheduler quantum
- ProcessPriorityClass.High, ProcessMemoryPriority normal, working-set
  minimum locked via SetProcessWorkingSetSizeEx(HARDWS_MIN_ENABLE)
- Fully reversed on toggle-off and on form close
- Off by default (battery cost on laptops); explicit opt-in per profile

MMCSS thread priority on hot threads bumped from High to Critical
(network listener, mix loop, render thread) — always on.

Network packet priority (always on, no toggle):
- qWAVE flow on the outbound UDP socket at QOS_TRAFFIC_TYPE_VOICE with
  QOS_NON_ADAPTIVE_FLOW (Voice priority, DSCP 46/EF, WMM Voice on Wi-Fi)
- Silent fallback if qwave.dll missing or QoS service disabled
- Sender + receiver kernel UDP buffers bumped to 1 MB each (was
  256 KB send / 512 KB receive) for resilience against ~30 ms stalls

Bug fix: PreferencesDialog logging toggle no longer flags the profile
as dirty. Logging is a machine-local AppConfig setting; the spurious
ChangedAnyProfileSetting flag was triggering the unsaved-changes prompt
on exit after toggling logs alone.

Manual updated: new "Use CPU and Windows performance settings in high
priority mode (Alt+U)" subsection on the Audio profile tab, new
"Network packet priority (qWAVE / Voice / WMM)" subsection in the
network chapter, Alt+U row added to keyboard-shortcuts table.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/RemSound.Core/Profile.cs

@@ -52,8 +52,17 @@ public sealed class Profile
     public int OpusFrameMilliseconds { get; set; } = 10;
     public int SendRateRaw { get; set; } = (int)SendRate.Standard;
     public bool TightLatencyMode { get; set; }
-    /// <summary>True suppresses the connect/disconnect sound cues. Off by default.
-    /// 2026-05-06.</summary>
+    /// <summary>True if this profile asks Windows to keep the RemSound process in
+    /// high-priority mode while it's running — CPU scheduling, power management, memory
+    /// priority, working-set lock, and MMCSS thread priority all elevated. Off by default;
+    /// the user opts in per profile when they want a "live session" feel where the
+    /// cold-start CPU ramp doesn't audibly hurt latency. On laptops that drains the
+    /// battery faster; on desktops it costs a couple of extra watts. See
+    /// <c>PerformanceMode</c> in the App project for the full lever list. Saved per
+    /// profile (not in AppConfig) because the right answer genuinely differs between
+    /// profiles.</summary>
+    public bool PriorityMode { get; set; }
+    /// <summary>True suppresses the connect/disconnect sound cues. Off by default.</summary>
     public bool MuteConnectionCues { get; set; }
     public int MaxLatencyMs { get; set; } = 80;
     public int Smoothness { get; set; } = 3;