Document full application landscape and collect Docker configs

- Add docs/landscape.md and docker-inventory.md with Mermaid architecture
- Add config/docker per host (db02, lake01, kafka01) and objectscale/elastic refs
- Add live architecture page at icons/docs/architecture.html
- Homepage OPS tab: Lakehouse Architecture group with diagram link
- Add scripts/collect/collect-fleet-config.sh to refresh configs from fleet

config/docker/README.md

@@ -0,0 +1,17 @@
+# Docker configurations
+
+Per-host Compose files and READMEs. These mirror (or document) live deployments.
+
+| Host | Path | Live location |
+|------|------|---------------|
+| atc-docker01 | `../compose/`, `../../deploy/` | `/root/lakehouse/compose/` |
+| atc-db02 | `atc-db02/docker-compose.yml` | `/opt/sources/docker-compose.yml` |
+| atc-lake01 | `atc-lake01/docker-compose.yml` | Docker CLI (no single compose file on host) |
+| atc-kafka01 | `atc-kafka01/docker-compose.yml` | Docker CLI |
+| atc-mgt01 | `../../compose/forgejo/` | Docker volumes |
+
+Refresh from fleet:
+
+```bash
+./scripts/collect/collect-fleet-config.sh
+```