Union in adaptive_images.py and field in adaptive_layout.py are both
imported but never used -- the last two Codacy findings on this PR,
matching the same fix already applied on PR #396.
CodeQL's path-injection flow still traced through _parse_render_request
after the scandir fix -- the tainted find_plugin_dir() result and the
scandir-derived _trusted_plugin_dir() result shared the same variable
name (plugin_dir), reassigned only on the truthy branch. That merge
point apparently isn't treated as a barrier by the flow analysis, so it
kept tracing the pre-reassignment value through to the manifest open().
Split into two distinct names -- candidate_dir (tainted, used only to
call _trusted_plugin_dir) and trusted_dir (the only name used for any
downstream file access) -- so there's no reassigned variable for the
flow to walk through.
CodeQL doesn't model Path.iterdir() as a taint-clearing enumeration the
way it does os.scandir() -- _trusted_plugin_dir's iterdir-based rebuild
still traced plugin_id through to the manifest.json open(). Switched to
scandir, matching the pattern already verified clean on PR #396.
Also stops surfacing raw exception text (update()/display() failures)
in the JSON render response -- logs full detail server-side via
exc_info instead, returning only the exception class name to the
client. And drops path values from three plugin_loader debug/error
logs that CodeQL flags as clear-text-logging of externally-influenced
data, keeping plugin_id (not flagged) for context.