feat: YAML LSP (/yaml endpoint) + IAC source catalog enrichment

- Add yaml-language-server (Node.js) to Dockerfile stage 3
- Add YAML_LSP_PORT=2090 env var (Dockerfile + ilsp.nomad)
- Start yaml-language-server in background thread (_serve_yaml_lsp)
- Expose /yaml WebSocket endpoint (same WS→TCP proxy as /python and /bicep)
- Load iac_source_catalog.json alongside bicep_modules_catalog.json
- Enrich param_completion_items() with descriptions + required flag from IAC source
  - Required params sorted first (sortText 0_lru_param_0_...) and marked with *
  - detail field shows * prefix for required params
- Update /health to report iac_source_modules + yaml_lsp fields
- Rewrite EDITOR_SETUP.md: WebSocket URLs, YAML schemas config for all editors
  (Helix, Neovim, PyCharm, VS Code) with azure-pipelines + gitea actions schemas
- All 35 tests pass

ilsp.nomad

@@ -106,6 +106,7 @@ job "ilsp" {
         HTTP_PORT        = "${NOMAD_PORT_http}"
         PYTHON_LSP_PORT  = "2087"
         BICEP_LSP_PORT   = "2088"
+        YAML_LSP_PORT    = "2090"
         DEVOPS_MCP_URL   = "https://devops-mcp.i80.dk"
         PYTHONUNBUFFERED = "1"
       }