v5 pre-release: multi-track drift fix, more self-tests, logging, CLI, version bump

Multi-track recording drift fix (Ed's question — can the separate tracks drift over an hour?):
 * Root: FlushPeerTracks skipped a peer that produced no samples in a render block, so a peer that
   went quiet long enough for its session to be pruned (>4 s idle) would have its track fall behind
   and desync. Now every peer track is padded to a full render block each cycle (silence when the
   peer produced nothing), so all peer tracks stay sample-locked to the single render clock — they
   can't drift apart however long the recording runs, and all end the same length. Same padding for
   the single-file bypass path. OnRecordBlockComplete now carries the block's float count.
   (The peer tracks are already resampled to the render clock per peer, so this makes peer-to-peer
   sync exact; your own "me" track is capture-clocked — same soundcard for capture+playback = same
   clock = no drift, different interfaces can drift slightly.)

 * Self-test: two new steps — "Per-peer shaping DSP" (PeerDspChain unity/master-off/volume/parametric
   + ParametricToPeaking) and "v5 settings and shaping round-trip" (AppConfig defaults, NamedPeers,
   MainTabOrder, parametric PeerShaping, recording default = Both).
 * Logging (gated by the logging checkbox): master shaping switch, EQ-mode change, parametric band
   add/delete, peer rename/clear/delete, and the applied Appearance settings after Preferences close.
 * CLI: --list-profiles and --list-named-peers (read-only), in --help.
 * Version bumped to 5.0; About-box changelog, RELEASE_NOTES.md and README updated for v5.

Build clean; --selftest passes.

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

RELEASE_NOTES.md

@@ -1,33 +1,49 @@
-# RemSound v4.9
+# RemSound v5.0
 
-Lock a profile to fixed addresses — for when you want one exact address and nothing else.
+A big release. Shape each person you're connected to, record everyone onto separate tracks, give your peers names that stick, and make the window your own with themes and reorderable tabs.
 
-## Lock to exact peer addresses
+## Shape each peer — volume, pan and EQ
 
-RemSound normally tries to be helpful about addresses: it finds the other computer by the name it advertises on your network, and if that computer turns up at a different address — a new IP after a reboot, or a second address over a VPN — it follows it there so your sound keeps flowing. Most of the time that's just what you want.
+A new **Volume, pan and EQ for peers** tab lets you treat every connected person as their own channel:
 
-Sometimes it isn't. If a machine is reachable at two addresses at once and you only ever want one of them, there's now a tickbox on the **Connectivity** tab:
+- **Volume** — an individual level for each person, so you can balance everyone against each other.
+- **Pan** — lean someone to the left or right. It keeps their stereo image; it never folds them down to mono.
+- **EQ** — change each person's tone with one of three equalisers: a simple **3-band** tone control, a **12-band graphic** EQ (31 Hz up to 16 kHz), or a **16-band parametric** EQ where you place each band yourself by typing a start frequency, an end frequency and a gain. On the parametric bands list, left and right arrow nudge the selected band by half a dB, live.
 
-**Lock to these exact peer addresses, no matter what (Alt+L)**
+Everything is live — you hear it as you move a control — and it adds no delay. One master switch turns it all on or off (there's a global shortcut for that too), and each person has a tick so you can bypass one without losing their settings. Crucially, **what you dial in is captured in your recordings**, so a shaped mix records the way it sounds (with a "record the raw audio" option if you'd rather keep it clean).
 
-With it ticked, that profile uses only the exact addresses you set. RemSound won't look the other computer up by name, and won't switch to any other address it discovers. If the address you set stops working, the connection simply waits (or drops) until that exact address is reachable again, rather than wandering off to another.
+## Record everyone on their own track
 
-It's off by default and saved with the profile, so you can lock one profile down while another keeps the automatic behaviour. When you use it, set your peers by their IP address (**Add peer by IP**) so there's no doubt which address is locked in.
+Recording can now **split into a separate file per peer** — each connected person on their own track — so you can take a jam or a conversation away and mix the parts afterwards. The default recording source is now "both sent and received".
+
+## Name your peers, and see who's who
+
+- **Rename peer (Alt+M or F2)** on the Connectivity tab gives someone a friendly name that sticks to their machine for good — across restarts, address changes and networks — and shows everywhere that peer appears.
+- **Peer details (Alt+E)** shows the highlighted peer's name, address, how long you've been connected, the link health and ping, what they're sending (how many devices, WASAPI or ASIO, sample rate and codec), and whether they're receiving your audio.
+- **Options → Manage named peers** lists everyone you've named, with where and when you last connected, so you can rename or delete them in one place.
+
+## Make it yours — Appearance
+
+Preferences has a new **Appearance** tab:
+
+- **Colour theme** — Match Windows (the default), Light, or Dark. RemSound now follows your Windows light/dark setting, has a modern font and its own app icon.
+- **Tab order** — reorder the main window's tabs with Move up / Move down, and hide the ones you don't use (including the volume/pan/EQ tab and the Discovered / Remembered peer lists on the Connectivity tab).
+- **Ctrl and a number** jumps straight to a tab by its position, following whatever order you've set.
 
 ## Compatibility
 
-**v4.9 talks to v3.3 through v4.8 with no trouble** — the over-the-network format is unchanged, so you don't have to update both ends at once. (Everyone still needs **v3.3 or newer**, where end-to-end encryption came in.)
+**v5.0 talks to v3.3 through v4.9 with no trouble** — the over-the-network format is unchanged, so 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-v4.9.zip` from this release.
+1. Download `RemSound-v5.0.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 v4.9 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 v5.0 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.