Hey, thanks for the detailed report, this was gold! Just pushed v8.9 and everything you flagged is in it:
Both bugs are fixed. The duplicate was a sneaky one: loot dropping while the equipment window was open silently shifted inventory positions, so equipping grabbed the wrong item and left a copy behind, the double-sell came from the same root cause. And good news: no need to send your save file. The game now auto-repairs affected saves on load, so any duplicates you already have will clean themselves up the first time you open v8.9.
The close button issue was the panel overflowing past shorter windows panels now cap to the screen and scroll, and you can also close any of them with Esc or by clicking outside.
Your suggestions all made it in too: there's an auto-buy toggle in the bottom bar now (made exactly for the Trials situation you described), a Salvage All button with a confirm tap, the Anomalies panel explains what they are and how they unlock (clearing phase 200), and craft cost now scales with phase the same way salvage value does, so the infinite Stardust loop is gone without touching the early-game economy.
Thanks again, reports like this are exactly what makes the game better. Keep 'em coming!