Orbit v0.9.1 — Smooth layout motion & reorderable repo tabs

Smooth layout

• Switching repos, collapsing the editor, maximizing the terminal panel, showing or hiding a panel and rearranging chats now animate as one short motion (220 ms) instead of jumping. Panels glide to the new repo's sizes together; terminals refit once at the end instead of redrawing at every step. Dragging a splitter stays immediate.
• A repo switch is a single movement: the editor's collapsed state comes from the saved session up front (previously it expanded and then collapsed again 400 ms later), the destination session is read in parallel with saving the current one, and the new repo's terminals appear as soon as the folder is open.
• No more flashes while switching: the sidebar keeps its views and the "Open folder…" state never shows during a switch.
• New setting Smooth panel transitions (on by default). It controls the animations directly and does not follow the OS "reduce motion" preference, which is permanently on when Windows' animation effects are turned off.

Repository tabs

• Drag to reorder the repo tabs in the top bar; the order is remembered with the window's session. A plain click still switches repo.
• The repo row is now centered in the top bar; when the tabs don't fit it fills the space and scrolls as before.

Notes

• No Rust changes: binary and installer sizes are unchanged.