2.6.0

Added: a date can say where it is on a map, and how to get in

venue_city answers "where is it" for a reader. It does not answer "is this within 50 km of me",
which is the question a regional invitation asks before it is sent and the one a map asks before it
draws a pin. Occurrences now carry venue_postal_code, latitude and longitude, indexed as
(brand_id, latitude, longitude) so a bounding box can narrow before anything is measured. The
postal code is a string: Austria writes A-1070, the Netherlands 1011 AB, and every five-digit
assumption breaks on the first concert across the border. The radius query itself is not here — it
belongs to whoever asks the distance question.

Ticketing rides along, because it is the same question about the same date. tickets_url and
is_free sit on the occurrence rather than the event: a tour sells each night separately, and an
event-level link would send everybody to the wrong night. is_free exists so that a missing link
reads as "free" instead of as "we forgot the link".

Fixed: the index-width guard no longer calls a DECIMAL unindexable

tests/Unit/IndexKeyLengthTest.php measured every column type it knew and reported the rest as
wider than InnoDB allows, which is right for text and json and wrong for decimal. A
decimal(10,7) occupies six bytes, not 3073, and the guard rejected the coordinate index at 6154
bytes against a 3072 limit. It now packs DECIMAL the way MySQL does, four bytes per nine digits
plus a tail on each side of the point, and knows float and double too.