fix(cctv): map WSDOT diagonal and BW compass codes; document WSDOT env

WSDOT's layer metadata defines BW (Bothways) plus the diagonals
NE/SE/SW/NW alongside N/E/S/W. Diagonal cameras were being demoted to the
low-confidence id-hash fallback; map them to 45/135/225/315 degrees and
treat BW (not B) as the no-single-facing code. Add CCTV_WSDOT_ENABLED and
CCTV_WSDOT_MAX_SOURCES to .env.example with the other pack controls.

.env.example

@@ -180,6 +180,8 @@ AISSTREAM_API_KEY=
 # CCTV_CALGARY_ENABLED=1                               # set 0 to disable the Open Calgary (Alberta) cameras
 # CCTV_CALGARY_MAX_SOURCES=220                         # cap cameras loaded from the Open Calgary catalog
 # CCTV_CALGARY_ROWS_URL=                               # override the Open Calgary catalog URL
+# CCTV_WSDOT_ENABLED=1                                 # set 0 to disable the WSDOT (Washington State) highway cameras
+# CCTV_WSDOT_MAX_SOURCES=250                           # cap cameras loaded from the WSDOT catalog, nearest Seattle/Spokane first
 # CCTV_MAX_SOURCES=4000                                # catalog-wide ceiling, shared round-robin across packs
 # CCTV_PREFER_AUSTIN=1                                 # prioritize Austin cameras in the registry
 # CCTV_FORCE_AUSTIN=                                   # force live default sources when a source-pack JSON is configured