권한 모드 동등화: Plan 추가 및 claw-code 권한 별칭 정규화 반영

- 전역 권한 모드를 Ask/Plan/Auto/Deny 4단계로 확장

- claw-code 계열 권한 값(default/acceptEdits/dontAsk/bypassPermissions) 입력 시 내부 모드로 정규화

- AgentContext 권한 판정 경로(전역/도구 오버라이드/패턴 오버라이드) 정규화 적용

- Chat/Settings UI에서 Plan 모드 노출 및 인라인 순환(Ask->Plan->Auto->Deny) 반영

- AppState/SettingsViewModel/SettingsService에 권한값 정규화 및 저장 시 일관성 적용

- Permission lifecycle 이벤트 메시지에 유효 모드 표기 보강

- 빌드/테스트 검증: dotnet build 경고0 오류0, dotnet test 372/372 통과

src/AxCopilot/Services/Agent/PermissionModeCatalog.cs

@@ -0,0 +1,72 @@
+namespace AxCopilot.Services.Agent;
+
+/// <summary>
+/// AX Agent permission mode constants and normalization helpers.
+/// Accepts legacy Ask/Auto/Deny values plus claw-code style aliases.
+/// </summary>
+public static class PermissionModeCatalog
+{
+    public const string Ask = "Ask";
+    public const string Plan = "Plan";
+    public const string Auto = "Auto";
+    public const string Deny = "Deny";
+
+    public static readonly IReadOnlyList<string> UserSelectableModes = new[]
+    {
+        Ask,
+        Plan,
+        Auto,
+        Deny,
+    };
+
+    /// <summary>
+    /// Normalize global permission mode.
+    /// Supported aliases: ask/auto/deny/plan plus default, acceptEdits, dontAsk, bypassPermissions.
+    /// </summary>
+    public static string NormalizeGlobalMode(string? value)
+    {
+        if (string.IsNullOrWhiteSpace(value))
+            return Ask;
+
+        return value.Trim().ToLowerInvariant() switch
+        {
+            "ask" => Ask,
+            "default" => Ask,
+            "plan" => Plan,
+            "auto" => Auto,
+            "acceptedits" => Auto,
+            "dontask" => Auto,
+            "deny" => Deny,
+            "bypasspermissions" => Deny,
+            _ => Ask,
+        };
+    }
+
+    /// <summary>
+    /// Normalize tool override permission.
+    /// Tool override is constrained to ask/auto/deny.
+    /// </summary>
+    public static string NormalizeToolOverride(string? value)
+    {
+        var mode = NormalizeGlobalMode(value);
+        return mode switch
+        {
+            Auto => "auto",
+            Deny => "deny",
+            _ => "ask",
+        };
+    }
+
+    public static bool IsAuto(string? mode) =>
+        string.Equals(NormalizeGlobalMode(mode), Auto, StringComparison.OrdinalIgnoreCase);
+
+    public static bool IsDeny(string? mode) =>
+        string.Equals(NormalizeGlobalMode(mode), Deny, StringComparison.OrdinalIgnoreCase);
+
+    public static bool RequiresUserApproval(string? mode)
+    {
+        var normalized = NormalizeGlobalMode(mode);
+        return !string.Equals(normalized, Auto, StringComparison.OrdinalIgnoreCase)
+               && !string.Equals(normalized, Deny, StringComparison.OrdinalIgnoreCase);
+    }
+}