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>

tests/Strata.SqlTools.Markdown.Tests/LinqToSql/QueryBreakdownGeneratorTests.cs

@@ -20,7 +20,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMermaidDiagram_SimpleLinqQuery_GeneratesValidMermaid()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21);
+        var query = TestDataContext.Users.Where(u => u.Age > 21);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -39,14 +39,14 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMethodChainDiagram_WithMethodCalls_ShowsChain()
     {
         // Arrange
-        var query = _context.Users
+        var query = TestDataContext.Users
             .Where(u => u.Age > 18)
             .OrderBy(u => u.Name)
             .Select(u => new { u.Id, u.Name });
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
-        var result = _generator.GenerateMethodChainDiagram(breakdown, "Method Chain");
+        var result = QueryBreakdownGenerator.GenerateMethodChainDiagram(breakdown, "Method Chain");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -66,7 +66,7 @@ public class QueryBreakdownGeneratorTests
         var breakdown = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateMethodChainDiagram(breakdown);
+        var result = QueryBreakdownGenerator.GenerateMethodChainDiagram(breakdown);
 
         // Assert
         Assert.That(result, Does.Contain("IQueryable"));
@@ -77,7 +77,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateCombinedDiagram_IncludesBothDiagrams()
     {
         // Arrange
-        var query = _context.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
+        var query = TestDataContext.Users.Where(u => u.Age > 21).OrderBy(u => u.Name);
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -95,7 +95,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMermaidDiagram_WithProjection_ShowsSelectedFields()
     {
         // Arrange
-        var query = _context.Users.Select(u => new { u.Id, u.Name, u.Email });
+        var query = TestDataContext.Users.Select(u => new { u.Id, u.Name, u.Email });
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -110,7 +110,7 @@ public class QueryBreakdownGeneratorTests
     public void GenerateMermaidDiagram_NullTitle_GeneratesWithoutTitle()
     {
         // Arrange
-        var query = _context.Users;
+        var query = TestDataContext.Users;
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
@@ -125,7 +125,7 @@ public class QueryBreakdownGeneratorTests
 // Test data context
 public class TestDataContext
 {
-    public IQueryable<User> Users => new List<User>().AsQueryable();
+    public static IQueryable<User> Users => new List<User>().AsQueryable();
 }
 
 public class User

tests/Strata.SqlTools.Markdown.Tests/LinqToSql/SqlStatementGeneratorTests.cs

@@ -21,7 +21,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query, "User Query Pipeline");
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query, "User Query Pipeline");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -42,7 +42,7 @@ public class SqlStatementGeneratorTests
         query.AddWhereClause("Age > 21");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query);
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Where Predicate"));
@@ -57,7 +57,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("Id, Name, Email", "Users");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query);
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Select Projection"));
@@ -72,7 +72,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateLinqPipelineDiagram(query, null);
+        var result = SqlStatementGenerator.GenerateLinqPipelineDiagram(query, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));