chore: initial import from KNEL/PFVCluster@041d311 [#769]

Split per O&M lane work order. Full history: KNEL/PFVCluster.
https://projects.knownelement.com/issues/769#note-4152

.shellcheckrc

@@ -0,0 +1,17 @@
+# ShellCheck configuration for PFVCluster
+# (used when running `shellcheck` directly; tests/shellcheck.sh applies the
+#  same disables via -e for consistent results under Docker)
+#
+# These checks are DISABLED because they flag intentional conventions of this
+# codebase, not bugs:
+#
+# SC1090 / SC1091 — cannot follow dynamically-computed `source` paths. The KNEL
+#   framework (vendor/) and test harness source helpers via computed include
+#   dirs, which shellcheck cannot resolve statically.
+# SC2029 — ssh orchestration (tests/remote.sh and perf/k8s/dns scripts)
+#   deliberately builds and expands the remote command on the CLIENT side before
+#   sending it. That is the whole point of the single-chokepoint remote pattern.
+disable=SC1090,SC1091,SC2029
+
+# Treat external-sourced files as bash (matches #!/usr/bin/env bash framework).
+external-sources=true