feat(evaluations): ATT&CK Evaluations importer for CrowdStrike Falcon [FASE-6.1]

- Migration b048: evaluation_imports table (adversary, round, status, tests_created)
- EvaluationImport SQLAlchemy model
- attck_evaluations_service: fetch rounds from evals.mitre.org API, import per-technique
  detection results (Technique/Tactic/Telemetry -> detected/partially/not_detected)
- All imported tests land in in_review state with lab-environment disclaimer
- Idempotency guard prevents duplicate round imports
- 4 new endpoints: list rounds, import specific, import latest, check-new
- Weekly APScheduler cron (Mon 06:00) auto-checks and imports new rounds
- SystemPage UI: rounds table, import buttons, check-new, result feedback
- Disclaimer callout reminding admins these are lab results not org coverage

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

backend/alembic/versions/b048_evaluation_imports.py

@@ -0,0 +1,39 @@
+"""Add evaluation_imports table.
+
+Revision ID: b048
+Revises: b047
+Create Date: 2026-06-05
+"""
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import UUID
+
+revision = "b048"
+down_revision = "b047"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "evaluation_imports",
+        sa.Column("id", UUID(as_uuid=True), primary_key=True),
+        sa.Column("adversary_name", sa.String, nullable=False),
+        sa.Column("adversary_display", sa.String, nullable=False),
+        sa.Column("eval_round", sa.Integer, nullable=False),
+        sa.Column("imported_at", sa.DateTime, nullable=False),
+        sa.Column("imported_by", UUID(as_uuid=True), sa.ForeignKey("users.id"), nullable=True),
+        sa.Column("tests_created", sa.Integer, default=0),
+        sa.Column("techniques_covered", sa.Integer, default=0),
+        sa.Column("status", sa.String, default="completed"),
+        sa.Column("notes", sa.Text, nullable=True),
+    )
+    op.create_index("ix_evaluation_imports_adversary", "evaluation_imports", ["adversary_name"])
+    op.create_index("ix_evaluation_imports_round", "evaluation_imports", ["eval_round"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_evaluation_imports_round", table_name="evaluation_imports")
+    op.drop_index("ix_evaluation_imports_adversary", table_name="evaluation_imports")
+    op.drop_table("evaluation_imports")