Release v4.6.1

Release: v4.6.1 [skip ci]

Patch

• Make: Gitignore .claude/ per-project settings (37c2d8f)
• Fix: Free table_positions in sz_sequence_intersect_serial and _ice (087ad7f)
• Fix: OOB read in sz_order_skylake tail for length-mismatched strings (a3926e2)
• Fix: Signed char handling in sz_find_byte_serial (#308) (267c757)
• Fix: OOB in sz_find_skylake / sz_rfind_skylake tail for null-byte needles (#312) (7d72c96)