Endless mode

You can now end an endless run and keep your score. Previously, once your engine got strong enough you basically couldn't lose, and "Forfeit Run" silently deleted everything with no leaderboard entry. There's now an "End Run & Record Score" button (in the pause menu during endless) that ends the run, submits your score to the leaderboard, and shows your final stats. Thanks Krzyak, GLY, and The Aphex Twin for the reports.
Endless difficulty ramps up properly now. The per-trip goal was only climbing ~$60-100, which was trivial against late-game earnings. The scaling curve is much steeper now — around 3x higher targets by the deep trips — so endless actually pushes back eventually. Thanks Krzyak and Elriel.
The campaign "Forfeit Run" also records your score now, instead of throwing the run away.
Balance

Consumables now have a hold cap of 5. There was no limit before, so you could hoard a huge stack and trivialize everything. Thanks Krzyak.
Nameless Coin nerfed: heads is now x3.75 (was x5.25), tails x0.5 (was x0.3). It was one of the bigger contributors to the "consumables feel OP" problem.
Fixes

Nameless Coin now shows the same multiplier everywhere. The tooltip said x5.25 but the on-screen coin flip showed x3.75 — the values are now consistent (x3.75 / x0.5) across the tooltip, the coin animation, and the result badge. Thanks Krzyak for catching it.
Thanks for all the detailed feedback — it genuinely shapes these updates. Keep it coming!