feat(calibre-server): Calibre Content Server as a boot-persistent Quadlet

lscr.io/linuxserver/calibre:9.15.0 (desktop build) running calibre-server
as the s6 main service on internal 8090 -> host 8084, auth-gated with a
plaintext userdb (mode 600) bootstrapped once by the deploy handler.
The desktop GUI is kept on 8080/8182, basic-authed with the same
credential pair via the machine-local env file.

scripts/deploy-plan.py

@@ -52,6 +52,7 @@ SERVICE_ORDER = (
     "copyparty",
     "jellyfin",
     "calibre-web",
+    "calibre-server",
     "plex",
     "tautulli",
     "prowlarr",
@@ -103,6 +104,7 @@ DANKSERVER_SERVICES = {
     "copyparty",
     "jellyfin",
     "calibre-web",
+    "calibre-server",
     "plex",
     "tautulli",
     "prowlarr",
@@ -353,6 +355,7 @@ def services_for_path(path: str, target: str) -> set[str]:
                 "romm": {"romm", "romm-mariadb", "romm-redis"},
                 "jellyfin": {"jellyfin"},
                 "calibre-web": {"calibre-web"},
+                "calibre-server": {"calibre-server"},
                 "copyparty": {"copyparty"},
                 "plex": {"plex"},
                 "tautulli": {"tautulli"},