Release v3.7: device-change smoothing, auto-tune spike rejection, wider mic detector, forensic logging

Coalesce capture-engine rebuilds (CompositeCaptureBackend): a swap-triggering
source change now arms a 250ms debounce timer and re-arms on each further
change, so a flap or quick reconfiguration produces ONE rebuild to the final
state instead of a burst (Andre's 16:40 four-rebuilds-in-33s crackle). In-place
updates still apply immediately; a pending rebuild whose target flaps back is
cancelled.

Auto-tune (TickRoute) now keys off the SECOND-highest arrival-gap/render-gap
second in the lookback window instead of the single worst, so a lone ~1s
OS/driver stall no longer balloons the buffer to the 200ms cap (the 16:51
trim burst); sustained jitter still reacts at full speed. Logs both gap-max
(true peak) and gap-used (value acted on).

Mic-privacy detector widened: also catches a per-app Deny aimed at this exe
under ConsentStore\microphone\NonPackaged\<exe>, the HKLM NonPackaged gate,
and the Group-Policy/MDM force-deny (AppPrivacy LetAppsAccessMicrophone=2) —
the block shapes that silence WASAPI capture while ASIO sails past, and that
the old three-value check missed.

Forensic instrumentation so the next log proves what happened: capPeak=
(loudest pre-encode sample, per lane, on the diag line), mic-privacy verdict
logged at startup, ui: capture tick/untick events, and device-event: lines for
Windows endpoint changes.

Docs: mic-privacy + auto-tune sections updated in readme.html, MANUAL.md
regenerated, About-box changelog and RELEASE_NOTES for v3.7.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/RemSound.App/AboutDialog.cs

@@ -20,6 +20,28 @@ internal sealed class AboutDialog : Form
     /// updates" path.</summary>
     private const string ReleaseNotes =
         """
+        RemSound v3.7
+
+        Changing audio devices mid-session is smoother. A quick
+        run of device changes now settles for a moment and
+        rebuilds the sound engine once, instead of several times
+        in a row — so reconfiguring no longer crackles.
+
+        The latency auto-tuner keeps its head when the computer
+        hiccups. A single brief stall no longer makes it balloon
+        the buffer; it only raises the cushion when late audio
+        keeps coming.
+
+        The microphone-privacy warning now also catches blocks
+        aimed at RemSound alone, and blocks set by an
+        administrator policy — kinds of block Windows applies
+        without showing you a switch.
+
+        RemSound's log now records the loudness of what you're
+        sending, the mic-privacy check's verdict, and every
+        device change — so if something goes wrong, the log can
+        prove what happened instead of leaving us guessing.
+
         RemSound v3.6
 
         Updating is far more reliable. RemSound now installs its