v1.6.1

Fixed — Migration pipeline

• MigrationRegistry::serialize_tag_string(): PHP true values now serialize as bare keys (e.g. showMidnight, not showMidnight:true) matching GB's boolean serialization convention
• apply_datetime_transforms(): smart_time and omit_current_year no longer auto-injected based on absence of old key (old defaults serialized as bare keys, so absence is ambiguous). Only explicit :false override maps definitively to new boolean: smart_time:false → showMidnight bare; omit_current_year:false → showCurrentYear bare
• apply_option_migration() now loops until stable (cap 16) so overlapping/cascading option-migration entries all apply in one converter call
• MigrationRegistry: added match_any_options entry field (OR semantics) alongside existing match_options (AND semantics); find_option_migration() and scanner in class-tag-converter.php honor it; group_option_entries_by_transform() includes it in signature + group data
• Added type:'option' MigrationRegistry entries for live datetime_single and datetime_range tags carrying pre-v1.6 option keys (date_time_field, time_field, start_field, start_time_field, end_field, end_time_field, separator, date_time_separator, fallback_text, format_type, custom_format, date_only, time_only, smart_time, omit_current_year) — covers partially-migrated tags where tag name was renamed but option keys were not
• Added type:'option' entries for remaining live base-tag legacy keys: fallback_text → fallback (text, content, title, permalink, image); via/from → src (all 7 base tags); type → use + custom_field value → key (content); return_type/fallback_url/field_key → as/fallback/key (image, term_image, try_image); legacy slot keys src_N/rel_N/key_N → v1.6 slot syntax (all try_ tags)