Bump pinned images to latest: authentik 2026.8.3, tautulli ls245, calibre-web ls402, plex 1.43.4

- authentik 2026.8.0 -> 2026.8.3 (server, worker, outpost quadlets)
- tautulli v2.18.1-ls242 -> v2.18.1-ls245
- calibre-web 0.6.27-ls397 -> 0.6.27-ls402
- plex 1.43.3.10896-ls322 -> 1.43.4.10903-ls325
- seerr already at v3.4.1 (latest, no bump)
- sync docs + the dead compose.yaml plex entry

anubis is already at the latest stable (v1.27.0); only pre-releases exist
beyond it, so no stable bump. Local-build images (caddy, alloy, loki,
comfyui, hermes) are refreshed by forced --no-cache rebuilds, not pins.

dankserver/compose.yaml

@@ -127,7 +127,7 @@ services:
   # Calibre-Web — e-book web frontend
   # ═══════════════════════════════════════════════
   calibre-web:
-    image: lscr.io/linuxserver/calibre-web:0.6.27-ls397
+    image: lscr.io/linuxserver/calibre-web:0.6.27-ls402
     container_name: calibre-web
     restart: unless-stopped
     environment: