chore(sonar)!: mark instance-data-free members static (CA1822)

Applied via `dotnet format analyzers --diagnostics CA1822 --severity info`.
12 files touched. The fixer also updated internal callers in tests to use
the type-name form (e.g. `gen.Method(x)` -> `Generator.Method(x)`); build
and full test suite remain green.

BREAKING CHANGE: two public methods become static and therefore can no
longer be invoked through an instance reference by external consumers:
- Strata.SqlTools.Markdown.LinqToSql.QueryBreakdownGenerator.GenerateMethodChainDiagram
- Strata.SqlTools.Markdown.LinqToSql.SqlStatementGenerator.GenerateLinqPipelineDiagram

Both are stateless utility methods on Generator classes — the static form
is the correct shape; the only callers in this repo already used the
type-name form. External code should change `gen.GenerateMethodChainDiagram(...)`
to `QueryBreakdownGenerator.GenerateMethodChainDiagram(...)`.

All other CA1822 hits in this commit are on private/protected members
(no public-surface impact).

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

src/Strata.SqlTools.Markdown/SqlServer/QueryBreakdownGenerator.cs

@@ -177,7 +177,7 @@ public class QueryBreakdownGenerator
     /// <summary>
     /// Escapes text for Mermaid diagram labels to prevent syntax errors.
     /// </summary>
-    private string EscapeMermaidText(string text)
+    private static string EscapeMermaidText(string text)
     {
         return text
             .Replace("\"", "&quot;")
@@ -194,7 +194,7 @@ public class QueryBreakdownGenerator
     /// <summary>
     /// Truncates text to a maximum length and adds ellipsis if needed.
     /// </summary>
-    private string TruncateText(string text, int maxLength)
+    private static string TruncateText(string text, int maxLength)
     {
         if (string.IsNullOrWhiteSpace(text) || text.Length <= maxLength)
         {