Show commit title, description, author and date on commit detail page

Added GitService.getCommitInfo() using getFullMessage() to preserve
the full commit body. Controller splits the message into title (first
line) and body (remainder) for separate display in the template.

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

src/main/resources/templates/commit.html

@@ -8,6 +8,20 @@
 
 <p><a th:href="@{/repo/{name}/commits(name=${name})}">&lt; Back to commits</a></p>
 
+<table border="0" cellpadding="4" cellspacing="0">
+<tr>
+<td><b>Author:</b></td>
+<td th:text="${commitInfo.author}"></td>
+</tr>
+<tr>
+<td><b>Date:</b></td>
+<td th:text="${commitInfo.date}"></td>
+</tr>
+</table>
+
+<h3 th:text="${commitTitle}"></h3>
+<pre th:if="${!commitBody.isEmpty()}" th:text="${commitBody}"></pre>
+
 <table border="0" cellpadding="4" cellspacing="0">
 <tr>
 <td>