fix(io): auto-scale GUI text with window size, consistent with the map

Body text/HUD font now derives from a window-relative auto-scale (starting
at uiScale, growing as the window grows) and is re-applied on resize, so the
text tracks the window like the map does. Ctrl +/- zoom still multiplies on
top of both. Removes the resize hiccup where only the map reacted.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Semesterprojekt/src/main/java/thb/jeanluc/adventure/io/SwingIO.java

@@ -120,6 +120,7 @@ public class SwingIO implements GameIO {
             @Override
             public void componentResized(ComponentEvent e) {
                 updateSideWidth();
+                applyFonts();
             }
         });
 
@@ -178,10 +179,21 @@ public class SwingIO implements GameIO {
         map.repaint();
     }
 
-    /** Re-derives and applies all component fonts from the current scale and zoom. */
+    /**
+     * Auto-scale derived from the window size relative to the design size
+     * (900x600). At the initial size this equals {@link #uiScale}; growing the
+     * window grows the text, mirroring how the map fits its panel.
+     */
+    private float frameScale() {
+        double s = Math.min(frame.getWidth() / 900.0, frame.getHeight() / 600.0);
+        return (float) Math.max(0.6, Math.min(2.6, s));
+    }
+
+    /** Re-derives and applies all component fonts from the window auto-scale and zoom. */
     private void applyFonts() {
-        float main = BASE_SIZE * uiScale * zoom;
+        float auto = frameScale();
-        float small = SMALL_SIZE * uiScale * zoom;
+        float main = BASE_SIZE * auto * zoom;
+        float small = SMALL_SIZE * auto * zoom;
         output.setFont(baseFont.deriveFont(main));
         input.setFont(baseFont.deriveFont(main));
         hud.setFont(baseFont.deriveFont(small));