Add email notification settings management

Implemented backend and frontend support for managing SMTP settings for email notifications. Includes API endpoints, database migration, and UI integration for configuring and testing email alerts.

backend/alembic/versions/0004_email_settings.py

@@ -0,0 +1,38 @@
+"""add email notification settings
+
+Revision ID: 0004_email_settings
+Revises: 0003_pg_stat_statements_flag
+Create Date: 2026-02-12
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "0004_email_settings"
+down_revision = "0003_pg_stat_statements_flag"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "email_notification_settings",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("enabled", sa.Boolean(), nullable=False, server_default=sa.text("false")),
+        sa.Column("smtp_host", sa.String(length=255), nullable=True),
+        sa.Column("smtp_port", sa.Integer(), nullable=False, server_default=sa.text("587")),
+        sa.Column("smtp_username", sa.String(length=255), nullable=True),
+        sa.Column("encrypted_smtp_password", sa.Text(), nullable=True),
+        sa.Column("from_email", sa.String(length=255), nullable=True),
+        sa.Column("use_starttls", sa.Boolean(), nullable=False, server_default=sa.text("true")),
+        sa.Column("use_ssl", sa.Boolean(), nullable=False, server_default=sa.text("false")),
+        sa.Column("alert_recipients", sa.JSON(), nullable=False, server_default=sa.text("'[]'::json")),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("email_notification_settings")