Bump to v1.5.0: cross-lane routing fix, recording double-tap fix, menu reorg

Bug fixes:
* BothIndependent recording was double-tapped — when both WASAPI and
  ASIO outputs were ticked, recordings came out garbled and ~2x the
  expected duration. AudioRecorder now uses four per-lane rings
  (sent-wasapi, sent-asio, recv-wasapi, recv-asio) plus a writer-
  thread mix step that drains min(wasapi, asio) frames and sum-mixes
  with the soft-tanh limiter. Tap signatures gained a RenderRoute
  parameter; Mixed maps to the wasapi slot.
* A peer announcing on the WASAPI lane was inaudible when the
  receiver only had an ASIO output ticked (and vice versa). The
  session opened, samples flowed into the SessionPlayout ring, but
  ReadForRoute(AsioLane) skipped any session whose Route was
  WasapiLane so nothing drained the ring. PlayoutEngine now tracks
  per-lane "is this lane backed by a device" via volatile bools
  settable through SetLaneActive(RenderRoute, bool), called from
  CompositeRenderBackend.SetOutputDevices whenever the device split
  changes. ReadForRoute admits orphan sessions when the other lane
  is inactive.

Menu reorganisation:
* New Options menu (Alt+O) holds Recording settings (Alt+S), Keyboard
  shortcuts (Alt+K, Ctrl+K), Startup behaviour (Alt+T), Preferences
  (Alt+P, Ctrl+P). Pre-v1.5 these were scattered across File menu,
  Record menu, and inside the Preferences dialog itself.
* Record menu mnemonic moved from Alt+O to Alt+K, rendered as
  "Record (Alt+K)" so the chord is visible despite K not being a
  letter in "Record". Alt+R is taken by Receive audio.
* File menu — new Recent profiles submenu (Alt+F, R) listing the
  five most-recently-opened profiles. Press 1..5 inside the submenu
  to jump to a slot. Missing files are skipped from the menu but
  kept in storage.
* Rename current profile moves to Alt+M (was R), Minimise to tray
  moves to Alt+N (was M).
* Lock to audio clock was Alt+K, now Alt+D.

UX additions:
* Ctrl+O = Open profile (matches the menu chord).
* New global hotkey: Start / Stop recording. Pickable from Options
  -> Keyboard shortcuts. Unbound by default. Works system-wide.

Wire format and audio pipeline unchanged from v1.4 — v1.4 and v1.5
peers interoperate.

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

src/RemSound.App/AboutDialog.cs

@@ -20,6 +20,57 @@ internal sealed class AboutDialog : Form
     /// updates" path.</summary>
     private const string ReleaseNotes =
         """
+        RemSound v1.5
+
+        Menu reorganisation, multi-peer audio-routing fix, recording
+        fix for BothIndependent mode, and Ctrl+O for Open profile.
+        Wire format and audio pipeline are unchanged — v1.4 and v1.5
+        peers interoperate.
+
+        Bug fixes:
+          * BothIndependent recording: when both WASAPI and ASIO
+            output devices were ticked, recordings came out garbled
+            and twice the expected duration. The recorder taps fired
+            from both lanes' render reads and the writer thread
+            appended both streams into one ring as if they were
+            sequential audio. Recorder now has per-lane rings and
+            mixes them in the writer thread.
+          * A peer announcing audio on the WASAPI lane was inaudible
+            when the receiver only had an ASIO output device ticked
+            (and vice versa). Sessions whose announced lane has no
+            active output now fall through to whichever lane IS
+            being read.
+
+        Menu reorganisation:
+          * New Options menu (Alt+O) holds: Recording settings,
+            Keyboard shortcuts, Startup behaviour, Preferences.
+            These used to be scattered across File menu (Keyboard
+            shortcuts, Preferences), Record menu (Recording settings),
+            and inside the Preferences dialog (Startup behaviour).
+          * Record menu mnemonic moved from Alt+O to Alt+K (rendered
+            as "Record (Alt+K)") so Alt+O could go to Options. K is
+            unusual for "Record" but the Record menu doesn't have a
+            natural free letter — Alt+R is taken by Receive audio.
+          * File menu: new Recent profiles submenu (Alt+F, R). Lists
+            the last five profiles you've opened, most-recent first.
+            Press 1..5 while the submenu is open to jump to a slot.
+            File → Rename current profile moves to Alt+F, M, and
+            Minimise to tray moves to Alt+F, N, to free up R for the
+            new submenu.
+          * Lock to audio clock (Audio profile tab) was Alt+K; now
+            Alt+D (the D in "audio") since the Record menu won Alt+K.
+
+        UX additions:
+          * Ctrl+O opens the Open profile dialog (matches the menu
+            chord). Previously the menu had no global shortcut.
+          * New global hotkey: Start / Stop recording. Pickable from
+            Options - Keyboard shortcuts. Unbound by default. Works
+            system-wide — RemSound doesn't need keyboard focus.
+
+        Recording feature unchanged in this release — the dialog
+        layout, formats (WAV / MP3 / OGG-Opus / FLAC), and tap-points
+        all the same as v1.4.
+
         RemSound v1.4
 
         Recording-settings dialog cleanup and a few mnemonic