Interpret flags and operands for completion

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Shell completion implementation plan
 
-Status: Stages 1–4 complete. Stage 5 is next.
+Status: Stages 1–5 complete. Stage 6 is next.
 
 Implement the [shell completion roadmap](completion.md) from baseline
 `2301872`. Follow the stages in order in one sprint. Intermediate stages may
@@ -184,6 +184,8 @@ The root package suite passes with `GOWORK=off` and `GOTOOLCHAIN=local`.
 
 ## Stage 5: Interpret flags and locate value positions
 
+Status: complete.
+
 1. Walk the completed tail using the same canonical and alias spellings and
    flag token rules as normal parsing. Factor shared token classification
    from `internal/cobra/flags.go` into neutral helpers where needed; keep
@@ -216,6 +218,15 @@ The root package suite passes with `GOWORK=off` and `GOTOOLCHAIN=local`.
    operands, terminators, and optional/repeated operands before a required
    suffix. Keep existing normal execution tests green at the sprint boundary.
 
+Completion: shared neutral token classification and flag lookup with normal
+parsing, and extracted operand count allocation for execution and completion.
+The completion walk records consumed flags and operands, locates pending or
+attached values, preserves entered prefixes, and filters canonical flag names
+by supplied identity. Tests cover aliases, short clusters, repeated flags,
+boolean assignments, option-looking values, terminators, interspersed operands,
+and operand cardinality. Root, adapter, and neutral metadata package tests pass
+with `GOWORK=off` and `GOTOOLCHAIN=local`.
+
 ## Stage 6: Assemble candidates and deliver query replies
 
 1. Produce a neutral result of candidate replacements, optional descriptions,