feat(printer): add cooling filter support flag and expose its toggle

cooling_filter_enabled existed as a config option but was shown nowhere,
and there was no capability flag to gate it. The cooling filter and air
filtration are alternative accessories sharing the same duct, so a
printer declares one or the other.

- new hidden printer capability flag support_cooling_filter
- "Use cooling filter" toggle in the Accessory group, shown only when
  the printer supports it; the air-filtration toggle hides in that case
  (no vendor restriction: third-party printers keep air filtration)
- explicit defaults (0) in the common machine base
- H2C declares support_cooling_filter=1 instead of support_air_filtration;
  its start-gcode already carries the cooling-filter conditional, so the
  toggle is functional. On H2C this drops the two exhaust-fan lines that
  air filtration emitted for ABS-class filaments, matching the printer's
  actual duct accessory; H2C is new on this branch so no existing user
  output changes.

Printers without the flag keep exactly the previous accessory UI and
g-code.

resources/profiles/BBL/machine/Bambu Lab H2C 0.4 nozzle.json

@@ -118,7 +118,7 @@
 		"14"
 	],
 	"support_chamber_temp_control": "1",
-	"support_air_filtration": "1",
+	"support_cooling_filter": "1",
 	"wrapping_exclude_area": [
 		"145x310",
 		"251x310",

resources/profiles/BBL/machine/fdm_machine_common.json

@@ -140,6 +140,8 @@
 	"silent_mode": "0",
 	"single_extruder_multi_material": "1",
 	"support_air_filtration": "0",
+	"support_cooling_filter": "0",
+	"cooling_filter_enabled": "0",
 	"support_chamber_temp_control": "0",
 	"support_fast_purge_mode": "0",
 	"support_object_skip_flush": "0",