chore(cctv-hk): changelog fragment and .env.example entries

Move the Hong Kong CCTV changelog entry into changelog.d/ (main now takes
fragments instead of CHANGELOG.md edits) and document CCTV_HK_ENABLED,
CCTV_HK_MAX_SOURCES and CCTV_HK_CAMERAS_URL beside the other packs.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.env.example

@@ -228,6 +228,9 @@ AISSTREAM_API_KEY=
 # CCTV_CALGARY_ROWS_URL=                               # override the Open Calgary catalog URL
 # CCTV_CATALONIA_ENABLED=1                             # set 0 to disable the Servei Català de Trànsit cameras
 # CCTV_CATALONIA_MAX_SOURCES=150                       # cap cameras loaded from Catalonia (~130 exist today)
+# CCTV_HK_ENABLED=1                                   # set 0 to disable the Hong Kong Transport Department cameras
+# CCTV_HK_MAX_SOURCES=1100                            # cap cameras loaded from Hong Kong (~1,013 exist today); min 8, max 1200
+# CCTV_HK_CAMERAS_URL=                                # override the DATA.GOV.HK camera locations XML URL
 # CCTV_KINGCOUNTY_ENABLED=1                            # set 0 to disable the King County (Washington) road cameras
 # CCTV_KINGCOUNTY_MAX_SOURCES=125                      # cap cameras loaded from the King County catalog
 # CCTV_WSDOT_ENABLED=1                                 # set 0 to disable the WSDOT (Washington State) highway cameras

changelog.d/990-hong-kong-cctv.md

@@ -0,0 +1,7 @@
+- Add Hong Kong Transport Department traffic snapshot cameras as a keyless CCTV
+  source pack: the public DATA.GOV.HK English locations XML, frames pinned to
+  `tdcctv.data.one.gov.hk`, with DATA.GOV.HK Terms of Use attribution. By
+  default nearly the full TD catalog (~1,013 cameras; cap 1,100) loads,
+  prioritized across Hong Kong Island, Kowloon and the New Territories. Headings
+  use the shared id-hash fallback at low confidence. `CCTV_HK_MAX_SOURCES` sets
+  the cap (8–1,200) and `CCTV_HK_ENABLED=0` turns the pack off (JCY2515, #990).