Cancel a reminder by voice, and honour a refusal (V-719)

reminder_cancel.go is a stateful pre-route resolver ahead of a parked
clarification and the statistical cascade. It accepts only an addressed
command-position imperative plus the reminder or alarm noun, so questions,
reported speech, past-tense reports and prohibitions establish no mutation
authority. Subject terms keep negation and quantity, and a parsed time
passes the same resolved-hour gate as capture.

One match cancels through the typed IPC method. Several are stored as
session candidates in the spoken order, capped at five, and only a whole
affirmative ordinal consumes that list: re-querying on the follow-up would
let a state change move the ordinal underneath him. No match, an unread
time, a spent ordinal and an ambiguous delivery result are all explicit
no-ops.

command_prohibition.go is the first mutation boundary in a turn. A direct
prohibition clears the three confirmation slots under their shared mutex,
so a later bare "да" cannot revive authority he has just revoked. A parked
clarify question is not authority and survives, suspended and repeated.
refusesCommand is the same belt at the executor entry points, checked
against the original utterance so a model rewriting Slots.Text cannot get
around it.

The rung is named in preRouteLadder, so /trace records whether it won or
declined on every surface.

--no-verify: master is the working branch this session by the owner's call.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

cmd/mavend/command_prohibition.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"context"
+
+	"github.com/kami/maven/internal/router"
+)
+
+// commandProhibitionReply is deliberately operation-neutral. At this boundary
+// Maven may know only that the user denied authority, not whether the model
+// would have called it a reminder, board transition, local tool or Hexis act.
+const commandProhibitionReply = "хорошо, не буду."
+
+// resolveCommandProhibition is the first mutation boundary in a turn. It runs
+// before a parked clarify answer or candidate selection can consume the words,
+// and before any route/model is consulted. A direct prohibition is complete in
+// itself: it needs no target lookup and makes no external call.
+//
+// A parked clarify request is unrelated state. Preserve it and say the pending
+// question again, using the same bounded suspend policy as every other side
+// request. Candidate lists likewise remain untouched; no ordinal was selected.
+func (h *reactiveHandler) resolveCommandProhibition(ctx context.Context, text string) (string, bool) {
+	if !router.IsCommandProhibition(text) {
+		return "", false
+	}
+	// A later bare "да" must not revive authority the user has just revoked.
+	// Confirmation slots are all mutation authority and are process-local, so
+	// clearing the three under their shared mutex is both conservative and
+	// atomic. Clarify questions and candidate lists are not authority and stay.
+	h.mu.Lock()
+	h.pending = nil
+	h.pendingHexis = nil
+	h.pendingRoutine = nil
+	h.mu.Unlock()
+	if h.clarifyStore != nil {
+		if q := h.clarifyStore.Get(dialogueIDOf(ctx), h.now()); q != nil {
+			h.noteSuspended(ctx, q)
+		}
+	}
+	return commandProhibitionReply, true
+}
+
+// refusesCommand is the defense-in-depth form for execution entry points which
+// can also be called with a reconstructed or test decision outside runTurn.
+// The sentinel cannot be renamed into an enabled function, and the original
+// utterance remains the authority even when a model rewrites Slots.Text.
+func refusesCommand(dec router.Decision) bool {
+	return dec.Slots.Fn == router.ProhibitedActFn || router.IsCommandProhibition(dec.Utterance)
+}