chore(lint): apply ruff --fix (4443 auto-fixes)

Auto-fixed categories:
- F401: unused imports removed
- I001: import blocks sorted
- W293: trailing whitespace stripped
- UP035: deprecated typing imports replaced
- SIM: simplify suggestions applied
- ARG: unused args prefixed with underscore
- T201: print statements removed
- F841: unused variables removed
- RUF059: unpacked variables prefixed

Remaining ~1500 unfixable errors (C901, B904, N806, E402) require manual work.

Backend smoke tests: 13/13 passed.

backend/src/scripts/clean_release_tui.py

@@ -9,9 +9,9 @@ import curses
 import json
 import os
 import sys
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from types import SimpleNamespace
-from typing import List, Optional, Any, Dict
+from typing import Any
 
 # Standardize sys.path for direct execution from project root or scripts dir.
 SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
@@ -28,11 +28,11 @@ from src.models.clean_release import (
     CleanProfilePolicy,
     ComplianceViolation,
     ProfileType,
+    RegistryStatus,
     ReleaseCandidate,
+    ReleaseCandidateStatus,
     ResourceSourceEntry,
     ResourceSourceRegistry,
-    RegistryStatus,
-    ReleaseCandidateStatus,
 )
 from src.services.clean_release.approval_service import approve_candidate
 from src.services.clean_release.artifact_catalog_loader import load_bootstrap_artifacts
@@ -124,7 +124,7 @@ class TuiFacadeAdapter:
             created_by=actor,
         )
 
-    def get_overview(self, *, candidate_id: str) -> Dict[str, Any]:
+    def get_overview(self, *, candidate_id: str) -> dict[str, Any]:
         candidate = self.repository.get_candidate(candidate_id)
         manifests = self.repository.get_manifests_by_candidate(candidate_id)
         latest_manifest = (
@@ -206,11 +206,11 @@ class CleanReleaseTUI:
         self.facade = TuiFacadeAdapter(self.repo)
         self.candidate_id = self._resolve_candidate_id()
         self.status: Any = "READY"
-        self.checks_progress: List[Dict[str, Any]] = []
-        self.violations_list: List[ComplianceViolation] = []
-        self.report_id: Optional[str] = None
-        self.last_error: Optional[str] = None
-        self.overview: Dict[str, Any] = {}
+        self.checks_progress: list[dict[str, Any]] = []
+        self.violations_list: list[ComplianceViolation] = []
+        self.report_id: str | None = None
+        self.last_error: str | None = None
+        self.overview: dict[str, Any] = {}
         self.refresh_overview()
 
         curses.start_color()
@@ -230,7 +230,7 @@ class CleanReleaseTUI:
         return repo
 
     def _bootstrap_demo_repository(self, repository: CleanReleaseRepository) -> None:
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         policy = CleanProfilePolicy(
             policy_id="POL-ENT-CLEAN",
             policy_version="1",
@@ -240,7 +240,7 @@ class CleanReleaseTUI:
             prohibited_artifact_categories=["test-data"],
             effective_from=now,
         )
-        setattr(policy, "immutable", True)
+        policy.immutable = True
         repository.save_policy(policy)
 
         registry = ResourceSourceRegistry(
@@ -257,10 +257,10 @@ class CleanReleaseTUI:
             updated_at=now,
             updated_by="system",
         )
-        setattr(registry, "immutable", True)
-        setattr(registry, "allowed_hosts", ["internal-repo.company.com"])
-        setattr(registry, "allowed_schemes", ["https"])
-        setattr(registry, "allowed_source_types", ["artifactory"])
+        registry.immutable = True
+        registry.allowed_hosts = ["internal-repo.company.com"]
+        registry.allowed_schemes = ["https"]
+        registry.allowed_source_types = ["artifactory"]
         repository.save_registry(registry)
         candidate = ReleaseCandidate(
             id="2026.03.03-rc1",
@@ -307,10 +307,10 @@ class CleanReleaseTUI:
         if not bootstrap_path:
             return
 
-        with open(bootstrap_path, "r", encoding="utf-8") as bootstrap_file:
+        with open(bootstrap_path, encoding="utf-8") as bootstrap_file:
             payload = json.load(bootstrap_file)
 
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         candidate = ReleaseCandidate(
             id=payload.get("candidate_id", "candidate-1"),
             version=payload.get("version", "1.0.0"),
@@ -523,7 +523,7 @@ class CleanReleaseTUI:
             result = self.facade.run_compliance(
                 candidate_id=self.candidate_id, actor="operator"
             )
-        except Exception as exc:  # noqa: BLE001
+        except Exception as exc:
             self.status = CheckFinalStatus.FAILED
             self.last_error = str(exc)
             self.refresh_screen()
@@ -563,7 +563,7 @@ class CleanReleaseTUI:
             self.violations_list = []
             self.checks_progress = []
             self.last_error = f"Manifest built: {manifest.id}"
-        except Exception as exc:  # noqa: BLE001
+        except Exception as exc:
             self.last_error = str(exc)
         self.refresh_overview()
         self.refresh_screen()
@@ -585,7 +585,7 @@ class CleanReleaseTUI:
         try:
             self.facade.approve_latest(candidate_id=self.candidate_id, actor="operator")
             self.last_error = None
-        except Exception as exc:  # noqa: BLE001
+        except Exception as exc:
             self.last_error = str(exc)
         self.refresh_overview()
         self.refresh_screen()
@@ -598,7 +598,7 @@ class CleanReleaseTUI:
         try:
             self.facade.publish_latest(candidate_id=self.candidate_id, actor="operator")
             self.last_error = None
-        except Exception as exc:  # noqa: BLE001
+        except Exception as exc:
             self.last_error = str(exc)
         self.refresh_overview()
         self.refresh_screen()
@@ -611,7 +611,7 @@ class CleanReleaseTUI:
         try:
             self.facade.publish_latest(candidate_id=self.candidate_id, actor="operator")
             self.last_error = None
-        except Exception as exc:  # noqa: BLE001
+        except Exception as exc:
             self.last_error = str(exc)
         self.refresh_overview()
         self.refresh_screen()