fix: preserve regex terms in global filters - #4194

Fixes #3971.

The global “Filter in any column” field split every literal space before passing terms to the existing condition parser. That turned /New York/ into two LIKE filters instead of one REGEXP filter.

This change adds a finite tokenizer at that lexical boundary. It preserves slash-delimited regex terms atomically, keeps ordinary space-separated terms as AND conditions, handles escaped slash parity, and falls back to the previous split behavior for malformed or unmatched slash input. Existing condition parsing, query construction, per-column filters, and project XML remain unchanged.

Tests cover:

• regex, ordinary, mixed, malformed, escaped-slash, whitespace, and parity cases
• the issue fixture through the real CondFormat and Query path (/New York/ returns exactly New York)
• ordinary multi-term AND behavior
• project filter save/restore behavior

Verification:

• SQLite Release build and install; all 5 tests pass
• SQLCipher Release build and install; all 5 tests pass
• regression tests fail when the tokenizer is replaced with the previous split-on-every-space behavior

Risk is limited to global-filter tokenization. Malformed slash input deliberately retains the previous behavior.