Release v4.3: speak status line (Tolk) + Logging tab with housekeeping

- New screen-reader hotkey "Speak the RemSound status information" (issue #13):
  reads the status line aloud through the active screen reader via Tolk, fires from
  anywhere (system-wide), unset by default. Built behind an IScreenReaderOutput seam
  so a future build can swap Tolk for Prism on Windows 10+ without touching callers.
  Tolk DLLs vendored under tolk/ and shipped next to the exe.
- New Logging tab in Preferences: Enable logs + Write logs now moved there, plus
  opt-in startup "warn if logs folder exceeds N MB" and "delete logs older than N days",
  and a "Delete all logs" button (Yes/No confirm). New LogMaintenance helper + AppConfig
  settings drive it.
- Manual (readme.html + regenerated MANUAL.md), About changelog and RELEASE_NOTES
  updated in plain English; csproj <Version> bumped to 4.3.

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

src/RemSound.App/IScreenReaderOutput.cs

@@ -0,0 +1,24 @@
+namespace RemSound.App;
+
+/// <summary>
+/// Abstraction over a screen-reader speech backend, so RemSound can speak text straight to whatever
+/// screen reader is running (NVDA, JAWS, SAPI, ...). Needed for feedback the screen reader can't
+/// otherwise observe — most importantly a GLOBAL hotkey firing while RemSound isn't focused, where
+/// NVDA reads nothing on its own.
+///
+/// Kept as an interface purely so the concrete backend can be swapped later without touching callers.
+/// Today the only implementation is <see cref="TolkScreenReaderOutput"/>, which works on every
+/// Windows version RemSound supports (including Windows 7). Prism (evaluated 2026-06-19) is the more
+/// modern option but hard-requires Windows 10+, so it can't replace Tolk while Win7 is supported — if
+/// that changes, add a PrismScreenReaderOutput and pick it per-OS in <see cref="ScreenReader"/>.
+/// </summary>
+internal interface IScreenReaderOutput
+{
+    /// <summary>Speak <paramref name="text"/> through the active screen reader. <paramref name="interrupt"/>
+    /// true cuts off whatever it's currently saying. Returns true if the text was handed to a screen
+    /// reader, false if none is available. Best-effort — never throws.</summary>
+    bool Speak(string text, bool interrupt = true);
+
+    /// <summary>Release the backend. Safe to call more than once.</summary>
+    void Shutdown();
+}