feat(iac): scaffold orca-platform layout (M1.1)

Lands the per-VM × per-service manifest tree, per-env overlays, VM specs
for SysEleven provisioning, DNS zone placeholder, plan/apply/validate
scripts, and a Makefile.

Structure (per INFRASTRUCTURE.md §2 + IMPLEMENTATION_PLAN.md M1.1):
- manifests/{vm-edge,vm-control,vm-data,stage}/<service>.toml — 35 stubs
- overlays/{dev,stage,prod}/overlay.toml — env-selection rules
- vms/{vm-edge,vm-control,vm-data,stage}.toml — OpenStack flavor/IP/firewall
- dns/yourplatform.com.zone.template — PowerDNS zone (body lands in M0.3)
- cluster.toml.tmpl — cluster-level config rendered per env
- scripts/validate.sh — TOML parse + structural sanity
- scripts/plan.sh — merge manifests + overlay → .orca-out/<env>/
- scripts/apply.sh — push to Orca controller (no-op until M1.2)
- Makefile — validate / plan / apply / diff / clean

Each manifest header names the milestone that finalises its real values;
images today are 'placeholder' for services that need their own repo to
exist first. make validate stays green; apply gates on ORCA_API_URL.

CI workflow swapped from the broken 'orca validate' to 'make validate',
which calls a Python TOML parser plus structural checks (placement.node
matches vm dir, resources.memory present, no mis-nested keys).

Refs: M1.1

Makefile

@@ -0,0 +1,35 @@
+# orca-platform — IaC for the Breakpilot Platform.
+#
+#   make validate              parse + structural sanity check every manifest
+#   make plan ENV=<env>        resolve manifests + overlay into .orca-out/<env>/
+#   make apply ENV=<env>       (M1.2+) push resolved set to Orca controller
+#   make diff ENV=<env>        alias for plan
+#   make clean                 remove .orca-out/
+
+.PHONY: help validate plan apply diff clean
+
+ENV ?=
+ORCA_API_URL ?=
+
+help:
+	@echo "orca-platform targets:"
+	@echo "  make validate              syntax + structural check (all manifests)"
+	@echo "  make plan ENV=<env>        resolve manifests for env (dev/stage/prod)"
+	@echo "  make apply ENV=<env>       push resolved set (no-op until M1.2)"
+	@echo "  make diff ENV=<env>        alias for plan"
+	@echo "  make clean                 remove .orca-out/"
+
+validate:
+	@./scripts/validate.sh
+
+plan:
+	@./scripts/plan.sh
+
+diff: plan
+
+apply:
+	@./scripts/apply.sh
+
+clean:
+	@rm -rf .orca-out
+	@echo "removed .orca-out/"