fix(gbfs): exclude stations with invalid coordinates

Reject non-numeric and out-of-range feed coordinates before they reach the
map or bike-share queries. Preserve numeric strings, aliases and zero.

Cover malformed records at the parser and public query boundaries.

Signed-off-by: Bortlesboat <[email protected]>

changelog.d/0-gbfs-invalid-coordinates.md

@@ -0,0 +1,3 @@
+- Skip bike-share stations with missing, blank or invalid coordinates instead
+  of placing them at coerced zero coordinates or accepting out-of-range values.
+  Explicit zero coordinates and numeric strings remain supported (Bortlesboat, #0).