feat(notifications): configurable OAuth2 authority + scope per SMTP configuration (defaults preserve M365) — entity + EF + migration + token service

Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj

src/ZB.MOM.WW.ScadaBridge.Commons/Entities/Notifications/SmtpConfiguration.cs

@@ -25,6 +25,20 @@ public class SmtpConfiguration
     /// <summary>Gets or sets the delay between retry attempts.</summary>
     public TimeSpan RetryDelay { get; set; }
 
+    /// <summary>
+    /// Gets or sets the OAuth2 token-endpoint authority template, or null to use the
+    /// Microsoft 365 default (<c>https://login.microsoftonline.com/{tenant}/oauth2/v2.0/token</c>).
+    /// The stored value is the full token-endpoint URL with an optional <c>{tenant}</c>
+    /// placeholder substituted from the credential's tenant id.
+    /// </summary>
+    public string? OAuth2Authority { get; set; }
+
+    /// <summary>
+    /// Gets or sets the OAuth2 scope requested from the token endpoint, or null to use the
+    /// Microsoft 365 default (<c>https://outlook.office365.com/.default</c>).
+    /// </summary>
+    public string? OAuth2Scope { get; set; }
+
     /// <summary>
     /// Initializes a new <see cref="SmtpConfiguration"/> with required fields.
     /// </summary>