v4.44.38 Schema Chain / Patch Layout Hotfix

Root cause:
- v4.44.37 full source contains ensure_v44437_schema() in config/config.php.
- supplied v4.44.37 PATCH was packaged one directory too deep (app/app/app/...).
- when deployed using the established patch workflow, active config/config.php could remain v4.44.36 while upgrade_v4_44_37.php called ensure_v44437_schema().

Fix:
- preserve ensure_v44437_schema() in active config/config.php.
- add ensure_v44438_schema() chained from v4.44.37.
- add defensive function_exists diagnostic in upgrade_v4_44_38.php.
- package PATCH relative to the actual application root (config/config.php, partials.php, etc.), without the extra app/app/app nesting.
- preserve Super Admin-only PAID -> UNPAID reversal, mandatory reason, per-item audit and KOPRA safeguards.
- no financial formula or historical ledger rewrite.
