Add default voice for each language (#180)

Fix https://github.com/kyutai-labs/pocket-tts/issues/166

pocket_tts/static/index.html

@@ -40,13 +40,15 @@
                 id="voice-url-input"
                 class="w-full border rounded p-2"
                 placeholder="hf://kyutai/tts-voices/alba-mackenna/casual.wav"
-                value="alba"
             />
             <p class="text-xs text-gray-500 mt-1">
                 Supports: http://, https://, or hf:// URLs.<br>
-                You can also use predefined voices:<br>
-                "alba", "anna", "azelma", "bill_boerst", "caro_davy", "charles", "eponine", "eve",
-                "fantine", "george", "jane", "jean", "mary", "michael", "paul", "peter_yearsley", "stuart_bell", "vera".
+                You can also use predefined voices (language code in parentheses):<br>
+                "alba" (en), "anna" (en), "azelma" (en), "bill_boerst" (en), "caro_davy" (en),
+                "charles" (en), "cosette" (en), "eponine" (en), "eve" (en), "fantine" (en),
+                "george" (en),  "jane" (en), "javert" (en), "jean" (en),
+                "marius" (en), "mary" (en), "michael" (en), "paul" (en),
+                "peter_yearsley" (en), "stuart_bell" (en), "vera" (en), "giovanni" (it), "lola" (es), "juergen" (de), "rafael" (pt), "estelle" (fr).
                 <br/>
                 You can find more voices in our
                 <a