chore(lint): auto-fix 253 of 283 ruff issues (F401, I001, E402, RUF100, UP037, SIM105)

Mass ruff auto-fix:
  - ruff check --fix: 109 issues fixed (F401 unused imports,
    I001 unsorted imports, UP037 quoted annotations, SIM105
    suppressible exception, RUF100 unused-noqa)
  - ruff check --fix --unsafe-fixes: 22 additional issues
  - ruff format: 70 files reformatted
  - Manual pass: fix 16 misplaced import httpx lines
  - Manual pass: fix remaining E402 (import-after-docstring)

Result: 283 errors -> 30 errors.

The remaining 30 are real issues that need manual review:
  5 F401 unused-import (likely auto-generated stubs)
  5 F821 undefined-name (real bugs in code that references
    redis/pydantic/LLMRegistry without imports)
  3 BLE001 (the compliance LLM fallback is intentional; the
    other two are real)
  3 RUF012 mutable-class-default
  3 SIM105, 3 SIM117, 2 E722, 2 E741
  1 B007, 1 B025, 1 E402, 1 RUF200 (pyproject.toml issue)

Tests: 436/437 pass (1 pre-existing SSE sandbox failure).
format check + import sort: now clean.
make ci: still gated on the 30 remaining real issues.
Follow-up: triage the 30 issues file-by-file.

stealth_engine.py

@@ -24,7 +24,13 @@ class StealthEngine:
 
     def generate_all(self) -> str:
         """Generate complete stealth script with all fingerprint protections."""
-        return self.webgl_noise() + self.canvas_noise() + self.audio_noise() + self.font_spoof() + self.webdriver_hide()
+        return (
+            self.webgl_noise()
+            + self.canvas_noise()
+            + self.audio_noise()
+            + self.font_spoof()
+            + self.webdriver_hide()
+        )
 
     def webgl_noise(self) -> str:
         """Add random noise to WebGL rendering to prevent GPU fingerprinting."""
@@ -87,7 +93,16 @@ class StealthEngine:
 
     def font_spoof(self) -> str:
         """Spoof system fonts to avoid font fingerprinting."""
-        fonts = ["Arial", "Helvetica", "Times New Roman", "Courier New", "Verdana", "Georgia", "Palatino", "Garamond"]
+        fonts = [
+            "Arial",
+            "Helvetica",
+            "Times New Roman",
+            "Courier New",
+            "Verdana",
+            "Georgia",
+            "Palatino",
+            "Garamond",
+        ]
         return f"""
         (() => {{
             const fonts = {json.dumps(fonts)};