chore(sonar): drop redundant inline init now set in ctor (S3604)

SqlServer/Breakdowns/QueryBreakdown.cs:26 — _clausesCacheDirty was both
initialized inline (= true) and re-assigned in the constructor at line 56.
Drop the inline initializer; the ctor remains authoritative.

The four nearby S3604 false-positives on clause backing fields stay
suppressed via #pragma — they are write-through targets of cache-invalidating
property setters.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdown.cs

@@ -23,7 +23,7 @@ public class QueryBreakdown : SqlBreakdownBase, IQueryBreakdown
 
     // Caching fields for GetClauses() performance optimization
     private SqlClauses? _cachedClauses;
-    private bool _clausesCacheDirty = true;
+    private bool _clausesCacheDirty;
 
     // Backing fields for clause properties to support cache invalidation
 #pragma warning disable S3604 // "Fields should not be write-only" - False positive: These fields are used as backing fields for properties that manage cache invalidation