v1.3-max-p21 — YouCut-style editor

Editor rebuilt to the standard mobile shape: large preview stage on top, horizontal clip timeline beneath (tap thumbnail to select, + appends), bottom tool bar that opens a contextual panel per tool (Trim/Speed/Volume/Rotate/Filter/Transition/Text/Sticker/Music/Ratio/Quality), Export/undo/redo/save-load in the top bar.

Signed arm64 release APK (58M). Untested on device. Commit 2907f59.