Restore centered placement prompt and snap preview line to the drop anchor

The instruction is back in the middle of the map and only says the one
thing left to do; the bottom bar is just Cancel/Next again. The dashed
preview now points at where the agent or ability will actually land
instead of the drag feedback's corner, using the same conversion the
drop uses. Pinned origins/landings are redrawn at full opacity above
the dimmed map so the pinned end is unmistakable.

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
954ee45961daraadedeji07 committed on 9/11/2026, 2:18:28 PMparent2f34bfb
4 files changedLine totals unavailable