Full lab documentation and infrastructure as code

- Trino catalogs, Grafana, Spark jobs, LDAP LDIF, NPM compose
- Airflow DAG scripts, Proxmox VM inventory, network docs
- Ansible playbook, Gitea CI validate workflow
- Backup and health-check scripts, cron documentation
- Homepage DOCS tab with links to all documentation
- Extended collect-fleet-config.sh and populate-repo.py

.gitea/workflows/validate.yml

@@ -0,0 +1,46 @@
+name: Validate Lakehouse config
+
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+    branches: [master, main]
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Validate YAML syntax
+        run: |
+          python3 -c "
+          import yaml, sys
+          from pathlib import Path
+          for p in Path('.').rglob('*.yaml'):
+              if '.git' in str(p): continue
+              try:
+                  yaml.safe_load(p.read_text())
+                  print('OK', p)
+              except Exception as e:
+                  print('FAIL', p, e)
+                  sys.exit(1)
+          for p in Path('.').rglob('*.yml'):
+              if '.git' in str(p) or 'workflows' in str(p): continue
+              try:
+                  yaml.safe_load(p.read_text())
+              except Exception: pass
+          "
+
+      - name: Validate Docker Compose
+        run: |
+          for f in deploy/*.yml compose/*/*.yaml compose/*/*.yml; do
+            [ -f "$f" ] || continue
+            docker compose -f "$f" config >/dev/null && echo "OK $f"
+          done
+
+      - name: Check required docs exist
+        run: |
+          test -f docs/landscape.md
+          test -f docs/network.md
+          test -f README.md