(index) Add score bonuses for single-word anchor tag spans

Enhanced scoring logic to add bonuses when the query matches single-word anchor (atag) spans exactly. Implemented this by adding conditions in `IndexResultScoreCalculator.java` and creating a new method `containsRangeExact` in `DocumentSpan.java` to check for exact span matches.

code/index/index-forward/java/nu/marginalia/index/forward/spans/DocumentSpan.java

@@ -103,13 +103,44 @@ public class DocumentSpan {
 
         for (int pi = 0; pi < positions.size(); pi++) {
             int position = positions.getInt(pi);
-            if (position < start) {
+            if (position >= start && position + len <= end) {
-                continue;
+                return true;
             }
 
-            if (position + len <= end) {
+            if (sei + 2 < startsEnds.size()) {
+                start = startsEnds.getInt(sei++);
+                end = startsEnds.getInt(sei++);
+            }
+            else {
+                return false;
+            }
+
+        }
+
+        return false;
+    }
+
+    /** Returns true if for any position in the list, there exists a range
+     * (position[i], position[i]+len] that is overlapped by a span */
+    public boolean containsRangeExact(IntList positions, int len) {
+        if (null == startsEnds || startsEnds.size() < 2 || positions.isEmpty()) {
+            return false;
+        }
+
+        int sei = 0;
+
+
+        int start = startsEnds.getInt(sei++);
+        int end = startsEnds.getInt(sei++);
+
+        for (int pi = 0; pi < positions.size(); pi++) {
+            int position = positions.getInt(pi);
+
+            if (position == start && position + len == end) {
                 return true;
-            } else if (sei + 2 < startsEnds.size()) {
+            }
+
+            if (sei + 2 < startsEnds.size()) {
                 start = startsEnds.getInt(sei++);
                 end = startsEnds.getInt(sei++);
             }

code/index/java/nu/marginalia/index/results/IndexResultScoreCalculator.java

@@ -386,6 +386,13 @@ public class IndexResultScoreCalculator {
                 {
                     score += 4; // If the title is a single word and the same as the query, we give it a verbatim bonus
                 }
+
+                var atagSpan = spans.getSpan(HtmlTag.ANCHOR);
+                if (atagSpan.length() == fullGroup.size
+                        && atagSpan.containsRangeExact(fullGroupIntersections, fullGroup.size))
+                {
+                    score += 4; // Add additional bonus if there's a single-word atag span
+                }
                 return;
             }
 
@@ -397,6 +404,13 @@ public class IndexResultScoreCalculator {
                 }
             }
 
+            // Bonus if there's a perfect match with an atag span
+            var atagSpan = spans.getSpan(HtmlTag.ANCHOR);
+            if (atagSpan.length() == fullGroup.size && atagSpan.containsRangeExact(fullGroupIntersections, fullGroup.size))
+            {
+                score += 1;
+            }
+
             // For optional groups, we scale the score by the size of the group relative to the full group
             for (var optionalGroup : constraints.getOptionalGroups()) {
                 int groupSize = optionalGroup.size;