fix(plex): advertise the plex.direct name, not the bare VIP (server vanished from the plex.tv account)

customConnections held two hand-typed URLs and neither could ever complete, so
Plex had nothing publishable and the server disappeared from the account:

  - https://192.168.2.24:32400 -- the server's cert is
    *.130072f20c334d6c8f63d0dfef87309b.plex.direct with NO IP SAN, so bare-IP
    https fails TLS for every client. Measured: a continuous storm of
    "CERT: incomplete TLS handshake ... certificate unknown" from real LAN
    clients arriving through the plex-l4-tcp VIP.
  - https://plex.home.keithjackson.dev:32400 -- nothing listens; the Gateway
    serves that host on 443 (measured http=000 against 192.168.2.20:32400).

With no completable connection plex.tv published nothing ("Mapped - Not
Published"), Plex fell back to Relay, and clients reported "not authorized".

Fix: advertise <dashed-ip>.<serverhash>.plex.direct -- public DNS that resolves
to the embedded address, so it points at the LAN VIP and matches the wildcard
cert. Verified with full TLS validation (no curl -k): 200 + verify OK, where
the bare-IP form fails to connect.

Declared as ADVERTISE_IP so git owns the value instead of a web form: the
image's 40-plex-first-run writes it into customConnections on every pod start,
outside the claim guard.

Does NOT fix off-LAN access -- the advertised address is RFC1918 and the WAN
tcp/32400 forward remains unverified. ManualPortMappingMode=1 with an absent
port is left as-is (no GitOps path exists for it).

Touches clusters/** -> sensitive paths -> needs the operator's
/approve-override, deliberately not self-posted (CLAUDE.md 1).

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

apps/wave-0/plex.yaml

@@ -137,6 +137,8 @@ spec:
             secretKeyRef:
               name: plex-claim
               key: PLEX_CLAIM
+        - name: ADVERTISE_IP
+          value: ${PLEX_ADVERTISE_URL}
         resources:
           limits:
             gpu.intel.com/i915: 1