feat(phases): implement webhooks (6.1), email (7.1), user preferences (7.2)

- Phase 6.1: WebhookConfig model, CRUD router (/api/v1/webhooks, admin-only),
  dispatch_webhook() with HMAC signing; integrated into test validation,
  campaign completion, and MITRE sync job
- Phase 7.1: SMTP email service with send_test_validated_email,
  send_campaign_completed_email, send_new_mitre_techniques_email;
  notify_role_with_email() added to notification_service
- Phase 7.2: notification_preferences and jira_account_id on User model;
  PATCH /users/me/preferences endpoint; Alembic migrations b031phase6 and b032phase7

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/alembic/versions/b032_phase7_user_prefs.py

@@ -0,0 +1,41 @@
+"""Phase 7.2: user notification_preferences and jira_account_id columns.
+
+Revision ID: b032phase7
+Revises: b031phase6
+"""
+from typing import Sequence, Union
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+from alembic import op
+
+revision: str = "b032phase7"
+down_revision: Union[str, None] = "b031phase6"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+_DEFAULT_PREFS = '{"email_on_test_validated": true, "email_on_campaign_completed": true, "email_on_new_mitre_techniques": false, "in_app_all": true}'
+
+def _column_names(table: str) -> set[str]:
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    return {c["name"] for c in insp.get_columns(table)}
+
+def upgrade() -> None:
+    user_cols = _column_names("users")
+    if "notification_preferences" not in user_cols:
+        op.add_column(
+            "users",
+            sa.Column("notification_preferences", postgresql.JSONB, nullable=True, server_default=_DEFAULT_PREFS),
+        )
+    if "jira_account_id" not in user_cols:
+        op.add_column(
+            "users",
+            sa.Column("jira_account_id", sa.String(100), nullable=True),
+        )
+
+def downgrade() -> None:
+    user_cols = _column_names("users")
+    if "jira_account_id" in user_cols:
+        op.drop_column("users", "jira_account_id")
+    if "notification_preferences" in user_cols:
+        op.drop_column("users", "notification_preferences")