Update colors (indigo→blue) and add credits to HTML

- Changed gradient to indigo→blue (cyan not allowed by HF)
- Added credits to HTML footer: Single-file by Nekochu
- Clarified credits in README

README.md

@@ -2,7 +2,7 @@
 title: Soprano TTS - Single File
 emoji: 🎧
 colorFrom: indigo
-colorTo: cyan
+colorTo: blue
 sdk: static
 short_description: Single self-contained HTML file for browser TTS
 app_file: index.html

index.html

@@ -85,7 +85,7 @@ footer a{color:var(--accent2);text-decoration:none}
     <div class="log" id="log"></div>
   </div>
 
-  <footer>Soprano by <a href="https://github.com/ekwek1/soprano" target="_blank">ekwek1</a> · ONNX port by <a href="https://huggingface.co/KevinAHM" target="_blank">KevinAHM</a> · Apache-2.0</footer>
+  <footer>Single-file by <a href="https://huggingface.co/Nekochu" target="_blank">Nekochu</a> · Soprano by <a href="https://github.com/ekwek1/soprano" target="_blank">ekwek1</a> · ONNX port by <a href="https://huggingface.co/KevinAHM" target="_blank">KevinAHM</a> · Apache-2.0</footer>
 </div>
 
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