Render images in file browser blob view

Add /repo/{name}/raw/{hash}/** endpoint serving binary file content
with correct Content-Type. Blob view detects image extensions (png,
jpg, gif, bmp, webp, svg, ico) and renders an <img> tag instead of
a <pre> text block.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/resources/templates/blob.html

@@ -25,7 +25,10 @@
 </table>
 
 <h3>Content</h3>
-<pre th:text="${content}">File content here</pre>
+<div th:if="${isImage}">
+<img th:src="@{/repo/{name}/raw/{hash}/{filePath}(name=${name}, hash=${hash}, filePath=${filePath})}" alt="" border="0">
+</div>
+<pre th:unless="${isImage}" th:text="${content}">File content here</pre>
 
 </body>
 </html>