an act with a target the system cannot have does not run (V-634)

V-633 gave tools spoken aliases, so a Russian act reaches a tool. It resolves
the verb only: the rest of the sentence became argv. "перезагрузи роутер" ran
as systemctl restart роутер, which is a real tool, a real word and a target
that cannot exist on this box. She then reported systemctl's own confusion as
if she had tried something sensible, and on a destructive row she spent a
confirm turn on it first.

The executor now refuses, ahead of the confirm gate, and names the word it
could not place. The check is the script and not a word list: a unit, a
container, a host and a path are ASCII here, so a Cyrillic argv element means
the alias match swallowed the verb and handed on the next word.

Process rows only. An MCP argument is not a target — a task title is Russian
and always was — and a house row drops the spoken args already.

It does not try to guess the right target. Identity is Nexus's, and a target
Nexus resolves reaches Hexis through handleHexisAct before this executor is
asked.

internal/tool/tool.go

@@ -39,6 +39,7 @@ import (
 	"os/exec"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/kami/maven/internal/ipc"
 	"github.com/kami/maven/internal/mcp"
@@ -73,6 +74,14 @@ var (
 	// confirm turn that would help: asking again would imply the second answer
 	// changes the outcome.
 	ErrNeedsAuthedSurface = errors.New("tool is irreversible and voice may not authorise it")
+	// ErrUnknownTarget — the act matched a tool and the target it carries cannot
+	// be one. A process row's args become argv for a real program, and a unit,
+	// container or host is named in ASCII on this box, so a Cyrillic tail is a
+	// word from the sentence rather than a target. Held apart from every failure
+	// above because the command never ran: forwarding it would spend a confirm
+	// turn on an act that cannot succeed, and then report the program's own
+	// confusion as if she had tried something sensible (V-634).
+	ErrUnknownTarget = errors.New("the act names a target the system cannot have")
 )
 
 // MCPCaller is the seam for an act that is an MCP tool call rather than a
@@ -144,6 +153,16 @@ func (e *Executor) Exec(ctx context.Context, name string, args []string, confirm
 	if t.Status != "enabled" {
 		return "", ErrNotEnabled
 	}
+	// A process row's args become argv, so the target has to be able to exist.
+	// Checked before the confirm gate below, because asking "выполнить X?" about
+	// an act that cannot run spends a turn on nothing (V-634). The other two
+	// dispatches are exempt: an MCP tool may take Russian text as an argument,
+	// since a task title is not a target, and a house row drops the spoken args.
+	if !isMCPRow(t.Cmd) && !isHouseRow(t.Cmd) {
+		if bad, ok := firstUnknownTarget(args); !ok {
+			return "", fmt.Errorf("%w: %q", ErrUnknownTarget, bad)
+		}
+	}
 	// The tier decides, not the column (Vikunja #449). RiskOf reads the row and
 	// answers the three questions the boolean never did: which acts are
 	// destructive, whether a confirm sticks (it never does), and what an
@@ -260,3 +279,37 @@ func (m *Matcher) Allowlist() []string { return m.names() }
 func (m *Matcher) Match(utterance string) (string, []string, bool) {
 	return router.DefaultActMatcher{Fns: m.names(), Aliases: m.aliases}.Match(utterance)
 }
+
+// firstUnknownTarget reports whether every arg could name something on this box,
+// and returns the first that could not.
+//
+// The check is the script, not a word list: this is not a fourth Russian
+// mechanism (CLAUDE.md § "Russian patterns"). A systemd unit, a container, a
+// host and a path are written in ASCII, so a non-ASCII rune in an argv element
+// means the alias match swallowed the verb and handed on the next word of the
+// sentence. "перезагрузи роутер" is the case: restart is a real tool and
+// "роутер" is a real word, and `systemctl restart роутер` is neither.
+//
+// It deliberately does not try to guess the right target. Identity is Nexus's
+// (CLAUDE.md § "The ecosystem"), and a target Nexus resolves reaches Hexis
+// through handleHexisAct before this executor is asked.
+func firstUnknownTarget(args []string) (string, bool) {
+	for _, a := range args {
+		for _, r := range a {
+			if r > unicode.MaxASCII {
+				return a, false
+			}
+		}
+	}
+	return "", true
+}
+
+func isMCPRow(cmd []string) bool {
+	_, _, ok := mcp.ParseCmd(cmd)
+	return ok
+}
+
+func isHouseRow(cmd []string) bool {
+	_, _, ok := smarthome.ParseCmd(cmd)
+	return ok
+}