Add core/type_utils.py with as_dict/as_list helpers, and
core/progress.py with a unified report_progress() callback.
Replace inline duplicated implementations of _json_safe_metadata(),
_as_list(), normalize_filename(), and per-source _report_progress()
with calls to the shared modules across downloader, matcher, resolver,
and all source modules (CivitAI, CivArchive, HuggingFace, LoRA Manager).
Extend filename normalization to include dots as separators.
