fix: reduce javadoc logo height to prevent navbar overflow

- Changed logo height from 100% to 2em
- Prevents logo from extending beyond navbar bounds
- Navbar height is 44px, 2em fits perfectly
- Tested in Chrome DevTools

Fixes #154

Author: sunJ0120

pom.xml

@@ -244,7 +244,7 @@
           </links>
           <excludePackageNames>io.github.treesitter.jtreesitter.internal</excludePackageNames>
           <header><![CDATA[
-          <img src="/tree-sitter/assets/images/tree-sitter-small.png" style="height:100%;width:auto;padding:0.4em" alt="logo"/>
+          <img src="/tree-sitter/assets/images/tree-sitter-small.png" style="height:2em;width:auto;padding:0.4em" alt="logo"/>
           ]]></header>
         </configuration>
       </plugin>