Move provider cost classification and reset-credit validation into a pure module while keeping localized output in main.qml. Preserve balance precedence, allowance bounds, provider exceptions, and the separate Codex monthly-credit contract.

Document module ownership and test coverage in the development guide. Regenerate the translation template without changing message IDs. TODO and user guides remain current; no user-visible change requires a changelog entry.

Verification: full make check passed in KDE neon with strict QML imports and no skips, including 1278 Qt cases and 95 Python tests. Package build and isolated installed/upgrade runtime checks passed for allowance and spend views.