fix: address Bandit B108/B110 across production code

B110 (try/except/pass):
- display_controller.py: narrow 'except Exception' to 'except AttributeError'
  for get_offset_frame() — plugins not having this optional method is the
  expected case, not all exceptions
- config_manager.py: B110 already resolved by the earlier removal of the
  dead secrets-loading block (the except/pass was inside it)
- All other except/pass blocks in src/ and web_interface/ are intentional
  (last-resort recovery, best-effort fallbacks, non-critical startup probes).
  Annotated each with # nosec B110 and a brief inline reason so the decision
  is explicit for future reviewers.
- Test files and plugin-repos B110 suppressed via Codacy API (not prod code).

B108 (/tmp usage):
- permission_utils.py: /tmp listed to PREVENT permission changes on it — not
  used as a temp path. Annotated # nosec B108.
- display_manager.py: fixed snapshot path is intentional (web UI reads same
  path); path-check guard also annotated.
- wifi_manager.py: named /tmp files match the sudoers allowlist installed with
  the system (the paths are hard-coded in both places by design). Annotated
  all six open/cp references # nosec B108.
- scripts/render_plugin.py: dev script default overridable by user. Annotated.
- web_interface/app.py: reads the same fixed path written by display_manager.
  Annotated # nosec B108.
- Test files suppressed via Codacy API.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/render_plugin.py

@@ -81,7 +81,7 @@ def main() -> int:
                         help='Plugin config as JSON string')
     parser.add_argument('--mock-data', '-m', default=None,
                         help='Path to JSON file with mock cache data')
-    parser.add_argument('--output', '-o', default='/tmp/plugin_render.png',
+    parser.add_argument('--output', '-o', default='/tmp/plugin_render.png',  # nosec B108 - dev script default; user can override
                         help='Output PNG path (default: /tmp/plugin_render.png)')
     parser.add_argument('--width', type=int, default=128, help='Display width (default: 128)')
     parser.add_argument('--height', type=int, default=32, help='Display height (default: 32)')