feat(tests): add comprehensive text-align test cases to fixtures/html (#313)

Author: Copilot

fixtures/html/text-rendering-test.html

@@ -64,6 +64,9 @@
     .align-center { text-align: center; }
     .align-right { text-align: right; }
     .align-justify { text-align: justify; }
+    .align-start { text-align: start; }
+    .align-end { text-align: end; }
+    .align-match-parent { text-align: match-parent; }
 
     /* Line Height Tests */
     .line-height-normal { line-height: normal; }
@@ -217,6 +220,21 @@ <h2 class="section-title">文本对齐测试 - Text Alignment Tests</h2>
         <div class="test-label">text-align: justify</div>
         <p class="align-justify">这是两端对齐的文本。This is justified text. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.</p>
       </div>
+      
+      <div class="test-item">
+        <div class="test-label">text-align: start</div>
+        <p class="align-start">这是起始对齐的文本。This is start-aligned text. Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
+      </div>
+      
+      <div class="test-item">
+        <div class="test-label">text-align: end</div>
+        <p class="align-end">这是结束对齐的文本。This is end-aligned text. Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
+      </div>
+      
+      <div class="test-item">
+        <div class="test-label">text-align: match-parent</div>
+        <p class="align-match-parent">这是匹配父元素对齐的文本。This is match-parent aligned text. Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
+      </div>
     </section>
 
     <!-- Line Height Tests -->