Close issue #26: minimap click-to-navigate already implemented

handleMinimapClick() in input.ts already intercepts clicks
within the minimap bounds, transforms to world coordinates via
projectMinimapToWorld(), and pans the camera smoothly. The
issue was filed before this was implemented.

Author: rgilks

docs/BACKLOG.md

@@ -4,16 +4,6 @@ Remaining work only. Completed items are in git history.
 
 ---
 
-## Open issues
-
-#### 26. Minimap is not interactive
-
-The minimap shows planet/ship positions but clicking it
-doesn't pan the main camera. Click-to-navigate would solve
-the "can't find my ship" problem.
-
----
-
 ## Maintenance
 
 ### Phase 5. Stronger entity state models