fix(tooling): star map generator outputs both SVG and PNG

Script now auto-converts to PNG after generating SVG. Tries magick,
convert, or rsvg-convert in order.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tooling/generate-star-map-svg.py

@@ -331,3 +331,23 @@ with open(output_path, 'w') as f:
 print(f'Written to {output_path}')
 print(f'{len(positions)} nodes, {len(starmap["edges"])} edges')
 print(f'Hops 0-{FOLD_HOP-1} individual, {FOLD_HOP}+ folded ({len(hop_groups.get(FOLD_HOP, []))} nodes)')
+
+# Also render PNG
+import shutil, subprocess
+png_path = output_path.replace('.svg', '.png')
+if shutil.which('magick'):
+    cmd = ['magick', '-density', '150', '-background', '#0a0a1a', output_path, png_path]
+elif shutil.which('convert'):
+    cmd = ['convert', '-density', '150', '-background', '#0a0a1a', output_path, png_path]
+elif shutil.which('rsvg-convert'):
+    cmd = ['rsvg-convert', '-d', '150', '-p', '150', '-b', '#0a0a1a', '-o', png_path, output_path]
+else:
+    cmd = None
+    print('No SVG-to-PNG converter found (tried magick, convert, rsvg-convert). PNG not generated.')
+
+if cmd:
+    result = subprocess.run(cmd, capture_output=True, text=True)
+    if result.returncode == 0:
+        print(f'PNG written to {png_path}')
+    else:
+        print(f'PNG conversion failed: {result.stderr.strip()}')