Resolve command context for completion

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Shell completion implementation plan
 
-Status: Stages 1–3 complete. Stage 4 is next.
+Status: Stages 1–4 complete. Stage 5 is next.
 
 Implement the [shell completion roadmap](completion.md) from baseline
 `2301872`. Follow the stages in order in one sprint. Intermediate stages may
@@ -148,6 +148,8 @@ Zsh, and Fish. Root and adapter package tests pass with `GOWORK=off` and
 
 ## Stage 4: Resolve the entered command context
 
+Status: complete.
+
 1. Add a private core completion request that separates completed words from
    the current word. Call `resolveEnteredRoute` on completed words only;
    use the snapshot's canonical metadata, resolved flag-alias context, and
@@ -172,6 +174,14 @@ Zsh, and Fish. Root and adapter package tests pass with `GOWORK=off` and
    child shadowed in the entered route, and flags beginning before the
    complete command path. Use existing routing rules as the oracle.
 
+Completion: added private request context resolution using completed words and
+the committed routing snapshot. Canonical child candidates are checked by
+resolving the entered route with the candidate inserted; discovery-only and
+unknown contexts do not invent command continuations. Tests cover canonical
+and aliased routes, chains, scoped and discovery flag aliases, shadowed
+children, runnable operand metadata, and paths ended by flags or operands.
+The root package suite passes with `GOWORK=off` and `GOTOOLCHAIN=local`.
+
 ## Stage 5: Interpret flags and locate value positions
 
 1. Walk the completed tail using the same canonical and alias spellings and