Add configurable SarifLevel property to ToolConfig

dotnet-diff-coverage.json

@@ -25,5 +25,6 @@
     "**/*.targets",
     "**/*.config"
   ],
-  "threshold": 0
+  "threshold": 0,
+  "sarifLevel": "note"
 }

src/DotnetDiffCoverage/Commands/RootCommandBuilder.cs

@@ -245,12 +245,12 @@
             var sarifReporter = services.GetRequiredService<SarifReporter>();
             if (outputSarif.Name == "-")
             {
-                await sarifReporter.WriteAsync(result, Console.OpenStandardOutput());
+                await sarifReporter.WriteAsync(result, Console.OpenStandardOutput(), config.SarifLevel);
             }
             else
             {
                 using var stream = outputSarif.Open(FileMode.Create);
-                await sarifReporter.WriteAsync(result, stream);
+                await sarifReporter.WriteAsync(result, stream, config.SarifLevel);
             }
         }
 

src/DotnetDiffCoverage/Config/ToolConfig.cs

@@ -12,7 +12,7 @@
     /// <summary>Glob patterns for non-source files to exclude from diff analysis entirely.</summary>
     public IReadOnlyList<string> ExcludePatterns { get; init; } = DefaultExcludePatterns;
 
-    /// <summary>Coverage threshold (0â100). Exit code 1 if uncovered % exceeds this.</summary>
+    /// <summary>Coverage threshold (0–100). Exit code 1 if uncovered % exceeds this.</summary>
     public double Threshold { get; init; } = 0.0;
 
     /// <summary>Default coverage format if not specified on CLI.</summary>
@@ -21,6 +21,9 @@
     /// <summary>Prefix to strip from coverage file paths before matching against diff paths.</summary>
     public string? CoveragePathPrefix { get; init; }
 
+    /// <summary>SARIF result level for uncovered lines. Valid values: "error", "warning", "note", "none".</summary>
+    public string SarifLevel { get; init; } = "warning";
+
     public static readonly IReadOnlyList<string> DefaultTestFilePatterns = new[]
     {
         "tests/**",

src/DotnetDiffCoverage/Output/SarifReporter.cs

@@ -24,13 +24,13 @@
         [property: JsonPropertyName("$schema")] string Schema,
         object[] Runs);
 
-    public async Task WriteAsync(CrossReferenceResult result, Stream stream)
+    public async Task WriteAsync(CrossReferenceResult result, Stream stream, string level = "warning")
     {
         var results = result.Files
             .SelectMany(f => f.UncoveredRanges.Select(range => new
             {
                 ruleId = "DC001",
-                level = "warning",
+                level,
                 message = new
                 {
                     text = range.Start == range.End