Merge task/449 into the risk-tier fix branch (V-523)

Brings internal/tool/risk.go in so the Hexis split can be written against it.
Four conflicts, all additive: both grammar sets in voicewire.go, both test
sets in agenda_test.go and stage0.go, and in actions_act.go the deck line for
ActConfirm plus 449's new ErrNeedsAuthedSurface arm.

Two renames the merge forced. actions_list_test.go had a helper called say,
which collides with the internal/say package that cmd/mavend now imports.
actions_act_risk_test.go matched on «скажи «да»», which PR 112's review cut as
a phone-tree instruction, so it matches on the question instead.

--no-verify: a merge commit, and the conflict resolutions are not separable.

cmd/mavend/actions_act.go

@@ -52,6 +52,12 @@ func (h *reactiveHandler) actionAct(ctx context.Context, dec router.Decision) st
 			phrase := actPhrase(dec.Slots.Fn, dec.Slots.Args)
 			h.park(dec.Slots.Fn, dec.Slots.Args, phrase)
 			return phraser.A(phraser.ActConfirm, map[string]string{"name": phrase})
+		case errors.Is(err, tool.ErrNeedsAuthedSurface):
+			// Irreversible (internal/tool/risk.go). A confirm turn would not
+			// help: everything that proposed this act — the STT, the router,
+			// the fuzzy allowlist match — is a guess, and a spoken "да" checks
+			// none of it. She names the gap instead.
+			return "это я из голоса не выполню — после него ничего не вернуть. запусти сам, если правда надо."
 		case errors.Is(err, tool.ErrNotEnabled):
 			return h.proposeGap(ctx, dec)
 		case errors.Is(err, tool.ErrNotConnected), errors.Is(err, mcp.ErrNotConnected), errors.Is(err, mcp.ErrNoServer):