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_template.py

@@ -1,16 +1,21 @@
 """TestTemplate model — predefined test catalog entries."""
 
+# Import uuid
 import uuid
 
+# Import Boolean, Column, DateTime, Index, String, Text,... from sqlalchemy
 from sqlalchemy import Boolean, Column, DateTime, Index, String, Text, func
+
+# Import UUID from sqlalchemy.dialects.postgresql
 from sqlalchemy.dialects.postgresql import UUID
 
+# Import Base from app.database
 from app.database import Base
 
 
+# Define class TestTemplate
 class TestTemplate(Base):
-    """
-    Predefined test template mapped to a MITRE ATT&CK technique.
+    """Predefined test template mapped to a MITRE ATT&CK technique.
 
     Templates come from several sources:
       - **atomic_red_team**: Atomic Red Team by Red Canary
@@ -19,24 +24,41 @@ class TestTemplate(Base):
 
     Users can instantiate a real Test from a template.
     """
+    # Assign __tablename__ = "test_templates"
     __tablename__ = "test_templates"
 
+    # 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 mitre_technique_id = Column(String, nullable=False)          # e.g. "T1059.001"
     mitre_technique_id = Column(String, nullable=False)          # e.g. "T1059.001"
+    # Assign name = Column(String, nullable=False)
     name = Column(String, nullable=False)
+    # Assign description = Column(Text, nullable=True)
     description = Column(Text, nullable=True)
+    # Assign source = Column(String, nullable=False)                      # atomic_red_te...
     source = Column(String, nullable=False)                      # atomic_red_team / mitre / custom
+    # Assign source_url = Column(String, nullable=True)
     source_url = Column(String, nullable=True)
+    # Assign attack_procedure = Column(Text, nullable=True)               # Suggested attack procedure
     attack_procedure = Column(Text, nullable=True)               # Suggested attack procedure
+    # Assign expected_detection = Column(Text, nullable=True)             # What blue team should detect
     expected_detection = Column(Text, nullable=True)             # What blue team should detect
+    # Assign platform = Column(String, nullable=True)                     # windows / linux...
     platform = Column(String, nullable=True)                     # windows / linux / macos
+    # Assign tool_suggested = Column(String, nullable=True)
     tool_suggested = Column(String, nullable=True)
+    # Assign severity = Column(String, nullable=True)                     # low / medium / ...
     severity = Column(String, nullable=True)                     # low / medium / high / critical
+    # Assign atomic_test_id = Column(String, nullable=True)               # ID in Atomic Red Team...
     atomic_test_id = Column(String, nullable=True)               # ID in Atomic Red Team repo
+    # Assign suggested_remediation = Column(Text, nullable=True)
     suggested_remediation = Column(Text, nullable=True)
+    # Assign is_active = Column(Boolean, default=True)
     is_active = Column(Boolean, default=True)
+    # Assign created_at = Column(DateTime(timezone=True), server_default=func.now())
     created_at = Column(DateTime(timezone=True), server_default=func.now())
 
+    # Assign __table_args__ = (
     __table_args__ = (
         Index('ix_test_templates_mitre_technique_id', 'mitre_technique_id'),
         Index('ix_test_templates_source', 'source'),