fix(imagery): refuse blank box edges at every conversion

Share-link integers and Cesium radians were converted before normalizeBox
checked them, so a blank edge still became 0°. Edges are now accepted only as
numbers or non-blank numeric strings, which also refuses [] and {}. Tests cover
all four edges through validateBox, dequantizeBox, boxFromRectangle and
searchHls.

CHANGELOG.md

@@ -32,7 +32,6 @@
 - Tool string length validation counts Unicode characters correctly, including characters outside the basic multilingual plane.
 
 - Director timeline seeks cross the dateline along the short longitude arc.
-- Recent Imagery refuses missing bounding-box edges instead of interpreting them as zero coordinates.
 
 - Recent Imagery’s exported `setBox` and `searchHls` reject missing, blank or
   boolean programmatic box edges instead of interpreting them as zero coordinates.