[LEGEND + HORIZONTAL] container inventory test

Testing a legend + a horizontal, tier-grouped container inventory.

Legend — color = container tier; shape = kind (rectangle = container · cylinder = data volume · document = admin config/secret):

flowchart LR
  lf["Front tier"]:::front
  la["App / data tier"]:::appt
  le["Egress"]:::egr
  li["Idle / on-demand"]:::idle
  lv[("Data volume")]:::data
  lc@{ shape: doc, label: "Config / secret" }
  class lc conf
  lf ~~~ la ~~~ le ~~~ li ~~~ lv ~~~ lc
  classDef front fill:#dcfce7,stroke:#16a34a,color:#14532d
  classDef appt fill:#e0e7ff,stroke:#6366f1,color:#312e81
  classDef egr fill:#fee2e2,stroke:#dc2626,color:#7f1d1d
  classDef idle fill:#f3f4f6,stroke:#9ca3af,color:#4b5563,stroke-dasharray:5 5
  classDef data fill:#fef3c7,stroke:#d97706,color:#78350f
  classDef conf fill:#dbeafe,stroke:#2563eb,color:#1e3a5f

Horizontal inventory (4 tier columns instead of an 8-box vertical stack):

flowchart LR
  subgraph front["Front tier"]
    direction TB
    web["`**web**
OpenResty (nginx + Lua)
_reverse proxy · rate + conn limits_
_serves /-/u/* uploads · publishes :80 :443_`"]
    cache["`**cache**
Redis 8.6.1 :6379
_presence · watchbar · login secrets_
_link-preview cache · auto-SSL storage_`"]
  end
  subgraph backt["App / data tier"]
    direction TB
    app["`**app**
JVM Java 11 · Play (Scala)
_talkyard-server :9000_
_React SSR in-JVM (Nashorn)_`"]
    rdb["`**rdb**
PostgreSQL 18.3 :5432
_all forum data_`"]
    search["`**search**
Elasticsearch 9.3.1 :9200
_full-text index_`"]
  end
  subgraph egrt["Egress"]
    direction TB
    egressp["`**egressp**
Smokescreen :4750
_SSRF-filtering egress proxy_
_read-only · cap_drop ALL_`"]
  end
  subgraph idlet["Idle / on-demand"]
    direction TB
    rendr["`**rendr**
debian-slim
_placeholder — no traffic today_`"]
    backup["`**backup**
pg_dumpall + gpg
_profile-only · on-demand_`"]
  end
  front ~~~ backt ~~~ egrt ~~~ idlet
  classDef front fill:#dcfce7,stroke:#16a34a,color:#14532d
  classDef appt fill:#e0e7ff,stroke:#6366f1,color:#312e81
  classDef egr fill:#fee2e2,stroke:#dc2626,color:#7f1d1d
  classDef idle fill:#f3f4f6,stroke:#9ca3af,color:#4b5563,stroke-dasharray:5 5
  class web,cache front
  class app,rdb,search appt
  class egressp egr
  class rendr,backup idle

End.