v0.1.5 — Faster cell rebalancing and MySQL compatibility

Dense card positions now rebalance in bounded batches while preserving the requested order and unique position constraint. Previously, a large cell needed two SQL updates per card, and an existing negative position could collide with the temporary pass. The new pass reserves positions absent from both old and final sets, including the signed integer boundary, before writing batches of at most 250 cards.

MySQL installations can migrate roles: Board's historical role import now quotes the reserved system column and requires the published naf/rbac 0.1.3 correction. Stored roles, grants and the schema remain unchanged; no additional migration is required.

Classic dark and system-dark primary actions now use a darker foreground, improving their rendered contrast from 2.77:1 to 5.87:1. Anthracite retains its own colors.

PHP 8.5.10 passed 540 tests with 1,771 assertions on both MariaDB 11.4 and MySQL 8.4.11. All 38 browser-module tests, PHP/JavaScript formatting and strict Composer validation passed. CI also passed on PHP 8.3 and 8.5 with both supported databases for the tagged merge commit. The actual move/version-conflict workflow remains unchanged.