caddy + pihole: make both boot-persistent and self-healing

Caddy left compose.yaml for a quadlet unit (caddy.service): joins
dankclaw_default for container-name upstreams, Pull=never for the local-only
image, Porkbun credentials via /home/dank/Containers/caddy/env written by
deploy from .env, bare-IP-catch-all health check. deploy_caddy installs,
enables, and starts the unit after retiring the bare container (state is in
host volumes).

Pi-hole: the repo now owns the sysctl drop-in
(dankclaw/pihole/sysctl/99-dnsmasq.conf, ip_unprivileged_port_start=53);
deploy_pihole installs it to /etc/sysctl.d/, stages conflicting later-sorted
drop-ins in the home trash, and applies 'sysctl --system' (the boot code
path). This fixes the 2026-08-26 crash loop (port-53 bind denied, restart
counter 1645) caused by a second drop-in resetting the value to 80.

Tests: new caddy_quadlet.bats seam; caddyfile/deployment_flow assertions
repointed from the removed compose service to the quadlet; pihole.bats pins
the sysctl drop-in and its deployment; test-changed.sh routes dankclaw/caddy/
and the pihole subtree to their seams. Docs: Caddy, Pi-hole, Dankclaw Stack,
work log.

dankclaw/compose.yaml

@@ -310,44 +310,8 @@ services:
       authentik-postgres:
         condition: service_healthy
 
-  # --- Reverse proxy + homepage (the homelab's single Caddy) ---------------
-  # The Caddyfile mounted here is the RENDERED copy (basicauth hash filled in
-  # from the host .env by scripts/deploy.sh); the repo copy carries the
-  # REPLACE_WITH_HASH placeholder. Certs/config live under
+  # Caddy (the homelab's single reverse proxy) left compose on 2026-08-26:
+  # it is boot-persistent via its Quadlet unit (dankclaw/caddy/quadlet/
+  # caddy.container), installed by deploy_caddy in scripts/deploy-remote.sh.
+  # The rendered Caddyfile, certs, and config still live under
   # /home/dank/Containers/caddy (rootless-writable).
-  caddy:
-    # Locally built: stock Caddy + the Porkbun DNS provider
-    # (dankclaw/caddy/Containerfile). See that file for build instructions.
-    image: franksdank/caddy-porkbun:latest
-    container_name: caddy
-    restart: unless-stopped
-    ports:
-      - "80:80"
-      - "443:443"
-    environment:
-      # Consumed by the Caddyfile's acme_dns block (DNS-01 wildcard certs).
-      PORKBUN_API_KEY: ${PORKBUN_API_KEY}
-      PORKBUN_API_SECRET_KEY: ${PORKBUN_API_SECRET_KEY}
-    volumes:
-      - /home/dank/Containers/caddy/Caddyfile:/etc/caddy/Caddyfile:ro
-      - /home/dank/Containers/caddy/data:/data
-      - /home/dank/Containers/caddy/config:/config
-      # The homepage: the host's /srv/homepage. The deploy copies the static
-      # files there; the status checker writes status.json and the deploy
-      # writes deployed.js there. (Not the repo's shared/homepage, which
-      # lacks the generated files.)
-      - /srv/homepage:/srv/homepage:ro
-    depends_on:
-      - authentik-server
-      - comfyui
-      - hermes
-      - grafana
-      - prometheus
-      - loki
-    healthcheck:
-      # The bare-IP catch-all answers 302 (curl -f passes on <400); this
-      # proves Caddy itself is serving without touching any upstream.
-      test: ["CMD", "curl", "-sf", "-o", "/dev/null", "http://localhost:80/"]
-      interval: 30s
-      timeout: 10s
-      retries: 3