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/app/models/evaluation_import.py

@@ -0,0 +1,34 @@
+"""SQLAlchemy model for tracking imported ATT&CK Evaluation rounds."""
+import uuid
+from datetime import datetime
+
+from sqlalchemy import Column, String, Integer, DateTime, Text, ForeignKey, Index
+from sqlalchemy.dialects.postgresql import UUID
+
+from app.database import Base
+
+
+class EvaluationImport(Base):
+    """Tracks which ATT&CK Evaluation rounds have been imported into the platform.
+
+    Each row represents one vendor+adversary combination that has been processed
+    and turned into Test records. Used to avoid duplicate imports and to show
+    the admin panel which rounds are available vs imported.
+    """
+    __tablename__ = "evaluation_imports"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    adversary_name = Column(String, nullable=False)        # "apt29", "turla"
+    adversary_display = Column(String, nullable=False)     # "APT29", "Turla"
+    eval_round = Column(Integer, nullable=False)           # 1, 2, 3 …
+    imported_at = Column(DateTime, nullable=False, default=datetime.utcnow)
+    imported_by = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=True)
+    tests_created = Column(Integer, default=0)
+    techniques_covered = Column(Integer, default=0)
+    status = Column(String, default="completed")           # "completed" | "failed"
+    notes = Column(Text, nullable=True)
+
+    __table_args__ = (
+        Index("ix_evaluation_imports_adversary", "adversary_name"),
+        Index("ix_evaluation_imports_round", "eval_round"),
+    )