Makefile: explicitly pass all identity env vars to setup_cell.py

DOMAIN_MODE, CELL_DOMAIN_NAME, CLOUDFLARE_API_TOKEN, DUCKDNS_TOKEN,
DUCKDNS_SUBDOMAIN are now explicit in the setup target so they are
visible and documented, not silently inherited from the environment.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Makefile

@@ -82,6 +82,11 @@ setup: check-deps
 	@sudo chown -R $${SUDO_USER:-$$(id -un)}:$${SUDO_USER:-$$(id -un)} config/ data/ 2>/dev/null || true
 	CELL_NAME=$(or $(CELL_NAME),mycell) \
 	CELL_DOMAIN=$(or $(CELL_DOMAIN),cell) \
+	DOMAIN_MODE=$(or $(DOMAIN_MODE),pic_ngo) \
+	CELL_DOMAIN_NAME=$(or $(CELL_DOMAIN_NAME),) \
+	CLOUDFLARE_API_TOKEN=$(or $(CLOUDFLARE_API_TOKEN),) \
+	DUCKDNS_TOKEN=$(or $(DUCKDNS_TOKEN),) \
+	DUCKDNS_SUBDOMAIN=$(or $(DUCKDNS_SUBDOMAIN),) \
 	VPN_ADDRESS=$(or $(VPN_ADDRESS),10.0.0.1/24) \
 	WG_PORT=$(or $(WG_PORT),51820) \
 	WG_PRIVATE_KEY="$(WG_PRIVATE_KEY)" \