Deliver shell completion query replies

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Shell completion implementation plan
 
-Status: Stages 1–5 complete. Stage 6 is next.
+Status: Stages 1–6 complete. Stage 7 is next.
 
 Implement the [shell completion roadmap](completion.md) from baseline
 `2301872`. Follow the stages in order in one sprint. Intermediate stages may
@@ -229,6 +229,8 @@ with `GOWORK=off` and `GOTOOLCHAIN=local`.
 
 ## Stage 6: Assemble candidates and deliver query replies
 
+Status: complete.
+
 1. Produce a neutral result of candidate replacements, optional descriptions,
    or a filesystem strategy with value context. Keep prefix preservation
    distinct from matching; the adapter translates the neutral replacement
@@ -259,6 +261,17 @@ with `GOWORK=off` and `GOTOOLCHAIN=local`.
    Use counter fixtures to prove target handlers, converters, factories,
    and providers are untouched. Verify no special dispatch without installation.
 
+Completion: connected the installed query before normal routing and reporting
+selection, assembled neutral candidates and filesystem strategies, and routed
+protocol output through managed reporting. Invalid transport requests return an
+error directive and a separate diagnostic; write failures remain presentation
+evidence. The adapter preserves short attached prefixes through a private cue
+consumed by the generated scripts, while retaining literal choice values and
+normalizing descriptions. Query tests cover empty and malformed requests,
+aliases and discovery, later registration, callback isolation, reporting flags
+as data, and writer failure. Root and adapter package suites and the full
+interactive Bash, Zsh, and Fish transport matrix pass.
+
 ## Stage 7: Annotate maintained commands and examples
 
 1. Annotate static format/scope flags where their choices already come from