feat(homepage): split AI fleet into role-based groups on a dedicated AI tab

Move the ~22-service flat "AI Systems" group off the Main tab into a new
four-tab layout (Main / AI / Infrastructure / Toolchain). The AI tab sorts
the inference fleet by function into seven groups:

  AI - Inference        gen, char-rp, char-rp-reasoning, Granite summarizer
  AI - Eval & Retrieval Selene, Skywork Reward, Qwen3 rerank/embed, image-bench
  AI - Gateways & Chat  LiteLLM, Asset Engine, Gateway Chat, Open WebUI, ...
  AI - Speech (TTS)     Chatterbox Fast, Kokoro, mOrpheus
  AI - Audio Tools      Parakeet ASR, YT Voice Clipper
  AI - Image & Media    ComfyUI, Arbo
  AI - Dormant          stopped rollback seats + retired auditions

Relabel each stack's homepage.group so canonical stacks/ matches the live
containers on ana-ml2, ana-docker, and irv-ml1. Dormant stacks were refreshed
with `docker compose up --no-start` so they carry the new label while staying
stopped (compose-start rollback preserved). settings.yaml drives tab/order/
columns; services.yaml and README updated to the new scheme.

configs/homepage/services.yaml

@@ -17,10 +17,13 @@
       siteMonitor: http://10.0.50.45:3001
       description: Uptime monitor (esh-docker-vm)
 
-# AI Systems group is fully Docker-auto-discovered (llama-swap, vLLM Embed,
-# vLLM Rerank — homepage.group=AI Systems on their compose files). Position
-# and row×3 style for the group live in settings.yaml. Do not add entries
-# here or they'll double up.
+# The AI tab is fully Docker-auto-discovered. Each inference service carries
+# a homepage.group=AI - <role> label on its compose file (AI - Inference,
+# AI - Eval & Retrieval, AI - Gateways & Chat, AI - Speech (TTS),
+# AI - Audio Tools, AI - Image & Media). Tab assignment, group order, and
+# column counts live in settings.yaml. Do not add entries here or they'll
+# double up. To move a service between AI groups, change the label on its
+# compose file and recreate the container (labels only apply on recreate).
 
 - Media:
   - Plex: