Add support for regex-based dictionary entries across the full stack:
Backend:
- DictionaryEntry model: add is_regex column (Boolean, default False)
- DictionaryEntryCRUD: validate regex on add_entry(), compile on creation
- _enforce_dictionary: match by regex pattern when is_regex=True
- dictionary_filter: support is_regex in filter/query
- metrics: include is_regex entries in metrics calculations
- Alembic migration: 20260604_add_is_regex_to_dictionary_entries
- Merge migration: 351afb8f961a (merge is_regex + composite index heads)
Frontend:
- DictionaryDetailModel: add is_regex field to DictionaryEntry interface,
EditForm, and addForm; sync edit/add form state with backend schema