Add CLI JSON value parsing

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Shared reporting and PromptKit v0.20.0 implementation plan
 
-Status: implementation in progress; Stages 1–4 complete.
+Status: implementation in progress; Stages 1–5 complete.
 
 ## Scope, authority, and execution
 
@@ -193,6 +193,10 @@ boundary; later documentation stages complete the integration inventory.
 
 ## Stage 5: Public CLI JSON parsing
 
+**Complete.** CLI JSON parsing and numeric conversion are implemented. Focused
+boundary tests and the root workspace suite (`GOTOOLCHAIN=local go test ./...`
+with Go 1.27.0) passed.
+
 Add `ParseCLIJSON(string) (any, error)` in core. Decode exactly one JSON value
 with `UseNumber`, require completion of that value, and recursively convert
 numbers under [OD-2](promptkit-v0.20.0.md#od-2-request-controls-and-provider-parameter-grammar).