Fix explicit anchor text to randomize term selection

Randomize anchor text list before trying terms so all explicit terms
are used across articles instead of always using the first term.

src/interlinking/content_injection.py

@@ -336,6 +336,10 @@ def _try_inject_link(html: str, anchor_texts: List[str], target_url: str) -> Tup
     Try to inject a link with anchor text into HTML
     Returns (updated_html, link_injected, anchor_text_used)
     """
+    # Randomize order to use different terms across articles
+    if anchor_texts and len(anchor_texts) > 1:
+        anchor_texts = random.sample(anchor_texts, len(anchor_texts))
+    
     for anchor_text in anchor_texts:
         # Try to find and wrap anchor text in content
         updated_html, found = _find_and_wrap_anchor_text(html, anchor_text, target_url)