refactor: Remove unused imports and add exception comments

Co-authored-by: jmiller-moko <230051081+jmiller-moko@users.noreply.github.com>

scripts/validate/auto_detect_platform.py

@@ -31,14 +31,13 @@ Exit codes:
 import argparse
 import hashlib
 import json
-import os
 import pickle
 import sys
 import xml.etree.ElementTree as ET
-from dataclasses import dataclass, asdict
+from dataclasses import dataclass
 from enum import Enum
 from pathlib import Path
-from typing import Dict, List, Optional, Tuple
+from typing import Dict, List, Optional
 
 
 # Version
@@ -146,6 +145,7 @@ class DetectionCache:
             with open(cache_file, 'wb') as f:
                 pickle.dump(result, f)
         except (pickle.PickleError, OSError):
+            # Ignore cache write failures: cache is optional optimization
             pass
 
     def clear(self) -> None:
@@ -154,6 +154,7 @@ class DetectionCache:
             try:
                 cache_file.unlink()
             except OSError:
+                # Ignore failures to delete cache files: stale cache entries are non-critical
                 pass
 
 
@@ -228,7 +229,6 @@ class PlatformDetector:
         indicators: List[str] = []
         metadata: Dict[str, str] = {}
 
-        manifest_patterns = ["**/*.xml"]
         skip_dirs = {".git", "vendor", "node_modules", ".github"}
 
         for xml_file in self.repo_path.glob("**/*.xml"):