Add comprehensive sign.html test and update documentation

- Add examples/sign.html with comprehensive extension compatibility testing
- Update README.md with profile fetching API documentation
- Update .gitignore for better file management
- Update examples/button.html and examples/modal.html with latest features

This completes the single-extension architecture implementation with:
- nos2x compatibility through true single-extension mode
- Method switching between extension/local/NIP-46/readonly
- Enhanced profile fetching for floating tab
- Comprehensive debugging and testing capabilities

examples/modal.html

@@ -37,7 +37,7 @@
   <script>
     document.addEventListener('DOMContentLoaded', async () => {
       await window.NOSTR_LOGIN_LITE.init({
-        theme: 'dark',
+        theme: 'default',
         methods: {
           extension: true,
           local: true,
@@ -48,12 +48,11 @@
         },
         floatingTab: {
           enabled: true,
-          hPosition: 0.7,        // 0.0-1.0 or '95%' from left
-          vPosition: 0.5,         // 0.0-1.0 or '50%' from top
+          hPosition: 1,        // 0.0-1.0 or '95%' from left
+          vPosition: 0,         // 0.0-1.0 or '50%' from top
           appearance: {
-            style: 'pill',        // 'pill', 'square', 'circle', 'minimal'
-            theme: 'auto',        // 'auto' follows main theme
-            icon: '[LOGIN]',      // Now uses text-based icons like [LOGIN], [KEY], [NET]
+            style: 'square',        // 'pill', 'square', 'circle', 'minimal'
+            // icon: '[LOGIN]',      // Now uses text-based icons like [LOGIN], [KEY], [NET]
             text: 'Login'
           },
           behavior: {