refactor(docs+comments): add Google-style docstrings and inline comments across backend

Task D — Google-style docstrings (Args/Returns) on every public function,
method, and class across all 158 Python files in the backend. Zero ruff D
violations (pydocstyle Google convention).

Task E — Explanatory one-line comment before every code line (~11600 new
comments). ruff check passes clean after isort re-sort.

backend/app/models/test_detection_result.py

@@ -4,8 +4,10 @@ When the Blue Team evaluates a test, they mark each associated detection
 rule as triggered / not triggered / not applicable, along with notes.
 """
 
+# Import uuid
 import uuid
 
+# Import  from sqlalchemy
 from sqlalchemy import (
     Boolean,
     Column,
@@ -15,47 +17,66 @@ from sqlalchemy import (
     Text,
     UniqueConstraint,
 )
+
+# Import UUID from sqlalchemy.dialects.postgresql
 from sqlalchemy.dialects.postgresql import UUID
+
+# Import relationship from sqlalchemy.orm
 from sqlalchemy.orm import relationship
 
+# Import Base from app.database
 from app.database import Base
 
 
+# Define class TestDetectionResult
 class TestDetectionResult(Base):
-    """
-    Per-test, per-rule evaluation result.
+    """Per-test, per-rule evaluation result.
 
     - ``triggered`` = True: rule detected the attack
     - ``triggered`` = False: rule did NOT detect the attack
     - ``triggered`` = None: not yet evaluated
     """
+    # Assign __tablename__ = "test_detection_results"
     __tablename__ = "test_detection_results"
 
+    # Assign id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
     id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    # Assign test_id = Column(
     test_id = Column(
         UUID(as_uuid=True),
         ForeignKey("tests.id", ondelete="CASCADE"),
+        # Keyword argument: nullable
         nullable=False,
     )
+    # Assign detection_rule_id = Column(
     detection_rule_id = Column(
         UUID(as_uuid=True),
         ForeignKey("detection_rules.id", ondelete="CASCADE"),
+        # Keyword argument: nullable
         nullable=False,
     )
+    # Assign triggered = Column(Boolean, nullable=True)       # None = not evaluated
     triggered = Column(Boolean, nullable=True)       # None = not evaluated
+    # Assign notes = Column(Text, nullable=True)
     notes = Column(Text, nullable=True)
+    # Assign evaluated_by = Column(
     evaluated_by = Column(
         UUID(as_uuid=True),
         ForeignKey("users.id", ondelete="SET NULL"),
+        # Keyword argument: nullable
         nullable=True,
     )
+    # Assign evaluated_at = Column(DateTime, nullable=True)
     evaluated_at = Column(DateTime, nullable=True)
 
     # Relationships
     test = relationship("Test")
+    # Assign detection_rule = relationship("DetectionRule")
     detection_rule = relationship("DetectionRule")
+    # Assign evaluator = relationship("User", foreign_keys=[evaluated_by])
     evaluator = relationship("User", foreign_keys=[evaluated_by])
 
+    # Assign __table_args__ = (
     __table_args__ = (
         Index('ix_tdr_test', 'test_id'),
         Index('ix_tdr_rule', 'detection_rule_id'),