Add PromptKit single smoke test command

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Dependency upgrades, discovery, and smoke testing implementation plan
 
-Status: Stages 1–10 complete; Stage 11 is next.
+Status: Stages 1–11 complete; Stage 12 is next.
 
 ## Authority and baseline
 
@@ -577,6 +577,15 @@ Run focused smoke command tests.
 **Complete when:** all single-kind bindings invoke the optional provider and
 faithfully report its result and errors.
 
+**Completed:** 2026-10-17. Added the optional `promptkit test KIND` command with
+all accepted scalar bindings, YAML preflight, prepared input/state, and native
+report delivery. Explicit zero/empty overrides remain present, omitted
+execution/retry overrides remain absent, and `all` is rejected before native
+request construction pending aggregate coordination. Assembled tests cover
+flag forwarding, findings, report-plus-error, nil-result contract failure, and
+short-write delivery. `GOTOOLCHAIN=local go test ./... -run
+'TestSmokeTestCommand' -count=1` passed in ckprompt.
+
 ## Stage 12: Coordinate aggregate smoke execution
 
 **Primary files:** smoke command runner, aggregate projection/outcome helpers,