Added a prompt injection detection (#857)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/Security/PromptInjectionFinding.cs

@@ -0,0 +1,31 @@
+using System.Text.Json.Serialization;
+
+namespace AIStudio.Tools.Security;
+
+/// <summary>
+/// One passage the runtime identified as a prompt-injection attempt and filtered out.
+/// </summary>
+/// <remarks>
+/// The property names are spelled out because the content stream is deserialized without a
+/// naming policy, so the names have to match what the runtime sends verbatim.
+/// </remarks>
+public sealed record PromptInjectionFinding
+{
+    /// <summary>
+    /// Which rule matched, e.g. "instruction_override".
+    /// </summary>
+    [JsonPropertyName("rule_id")]
+    public string RuleId { get; init; } = string.Empty;
+
+    /// <summary>
+    /// The rule's family, e.g. "exfiltration".
+    /// </summary>
+    [JsonPropertyName("category")]
+    public PromptInjectionFindingCategory Category { get; init; } = PromptInjectionFindingCategory.UNKNOWN;
+
+    /// <summary>
+    /// The passage as it appeared in the content, so the user can see what was removed.
+    /// </summary>
+    [JsonPropertyName("snippet")]
+    public string Snippet { get; init; } = string.Empty;
+}