fix: drive compile progress from ninja's [done/total] counter (#285)

The compile slice advanced a fixed step per line of build output, so how
far it moved depended on how many lines the build printed. When aurora and
its dependencies are compiled locally (as on macOS) the bar reached its cap
long before the game itself was compiled. Read ninja's edge counter instead.

Launcher/WiiCompiled.Setup.Linux/InstallProgress.cs

@@ -184,18 +184,31 @@ internal sealed class BuildProgressWindow
         }
 
         // Anything else - a plain MKWCBUILD note, or raw tool output - stays a diagnostic and only
-        // feeds the heartbeat below.
+        // feeds the compile progress below.
         _reporter.Diagnostic(line);
-        // Compilation announces itself once and then emits thousands of compiler lines. Treat that
-        // output as a heartbeat so the slice keeps creeping forward, but only publish a progress
-        // line when the rounded percentage actually changes.
-        if (_fraction >= CompileFraction)
+        // Compilation announces itself once and then ninja prefixes every edge with [done/total].
+        // Follow that counter rather than counting lines: how many lines a build prints depends on
+        // whether aurora and its dependencies are prebuilt (AppImage) or compiled here (macOS), so a
+        // fixed per-line step reached the top long before the game itself compiled.
+        if (_fraction >= CompileFraction && TryParseNinjaProgress(line, out var done, out var total))
         {
-            _fraction = Math.Min(0.97, _fraction + 0.0015);
+            _fraction = Math.Max(_fraction, CompileFraction + (0.97 - CompileFraction) * done / total);
             Emit();
         }
     }
 
+    private static bool TryParseNinjaProgress(string line, out int done, out int total)
+    {
+        done = total = 0;
+        if (!line.StartsWith('[')) return false;
+        var close = line.IndexOf(']');
+        var slash = line.IndexOf('/');
+        return close > 0 && slash > 0 && slash < close
+            && int.TryParse(line.AsSpan(1, slash - 1), out done)
+            && int.TryParse(line.AsSpan(slash + 1, close - slash - 1), out total)
+            && total > 0 && done <= total;
+    }
+
     private void Emit()
     {
         var percent = Interpolate(_fraction);