Release prep v5.3: version bump, About changelog, release notes

- csproj <Version> 5.2 -> 5.3.
- About box: prepend the v5.3 entry (single-app sending, lock-screen service,
  freer ASIO driver switching).
- RELEASE_NOTES.md rewritten for v5.3.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

RELEASE_NOTES.md

@@ -1,36 +1,47 @@
-# RemSound v5.2
+# RemSound v5.3
 
-A stability and polish release. No new features — this one is bug fixes and internal tidy-ups from a deep code review, so it should just feel a bit more solid.
+Send a single application's sound, and stream a machine from its lock screen. Plus freer use of pro (ASIO) sound cards.
 
-## Fixes you might notice
+## Send one application, not the whole device
 
-- **Changing the codec or send rate while streaming** could, in rare cases, crash RemSound with no warning. Fixed.
-- **Recording "both sent and received" into a single file** could lose small amounts of audio and drift out of sync over a long session. It now stays sample-accurate for the whole recording.
-- **After installing**, RemSound now honours your "start minimised" setting on the first relaunch (and still comes to the front when you're not starting minimised).
-- **Uninstalling** one copy no longer switches off a different copy's "run at startup".
-- Starting a split "received only" recording with **no peers connected** now tells you clearly, instead of quietly making an empty folder.
-- The **clipping indicator** in the diagnostics works again.
+Until now you sent a whole audio device — everything coming out of your PC. In the send list you can now choose a **specific application** instead: just your music player, just your game, just a call. Only that program's sound goes out; the rest of your PC stays private.
 
-## Under the hood
+- Tick any app that's **currently making sound**, or **name an app** so RemSound catches it the moment it opens.
+- Whole-device sending works exactly as before — this is an extra choice, not a replacement.
 
-- The automatic-update restart now brings the window to the front, the same way the installer does.
-- The router port opened by UPnP is properly removed when you close RemSound.
-- Lighter on memory and disk — fewer background file reads while you work, and tidier release of resources when the window closes or switches profiles.
+## Stream from the lock screen, before anyone signs in
+
+There's a new, **optional RemSound service**. It can send a machine's audio from the Windows **lock screen** — so you can hear a computer that's powered on but not yet logged in, which the normal app can't do because nothing runs until you sign in.
+
+- Install it **once**, from the RemSound installer (it offers to set it up for you). It needs administrator rights that one time only.
+- It runs quietly in the background and **steps aside automatically** the instant you open RemSound normally, handing the audio back to the app.
+- It **updates itself** whenever RemSound updates — there's nothing to maintain.
+
+If you never want it, don't install it: nothing about the normal app changes.
+
+## Freer with professional (ASIO) sound cards
+
+- You can now **switch between ASIO drivers** while RemSound is open.
+- RemSound **releases the sound card** when it isn't using it, so another program (a DAW, for example) can take it over instead of being locked out.
+
+## Also
+
+- Per-application sending is fully wired through the app, and a range of fixes and internal tidy-ups from continued review.
 
 ## Compatibility
 
-Nothing about the over-the-network format changed, so **v5.2 talks to v3.3 through v5.1** with no trouble — you don't have to update both ends at once. (Everyone still needs **v3.3 or newer**, where end-to-end encryption came in.)
+Nothing about the over-the-network format changed, so **v5.3 talks to v3.3 through v5.2** with no trouble — you don't have to update both ends at once. (Everyone still needs **v3.3 or newer**, where end-to-end encryption came in.)
 
 ## Install
 
-1. Download `RemSound-v5.2.zip` from this release.
+1. Download `RemSound-v5.3.zip` from this release.
 2. Close RemSound.
 3. Extract the zip **over your existing RemSound folder**, overwriting program files when prompted. The zip is program files only — it won't touch your settings, profiles, logs or recordings.
 4. Run `RemSound.exe`.
 
 ## Upgrading
 
-**From v3.6 or newer:** Help → Check for updates installs v5.2 with the in-app updater — and if it can't finish, it puts your old version back exactly as it was.
+**From v3.6 or newer:** Help → Check for updates installs v5.3 with the in-app updater — and if it can't finish, it puts your old version back exactly as it was.
 
 **From v1.9–v3.5:** Check for updates works, but uses your current version's older updater for this one hop. If auto-update has been failing on your machine, install by hand using the steps above.