feat(sense): establish M1 offline intake skeleton

Sense/internal/onvif/unavailable.go

@@ -0,0 +1,20 @@
+package onvif
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// UnavailableAdapter keeps the process boundary explicit until T-006 supplies
+// a real, whitelist-validated ONVIF adapter. It must not be mistaken for a
+// compatibility implementation.
+type UnavailableAdapter struct{}
+
+func (UnavailableAdapter) Probe(context.Context, Target) (ProbeResult, error) {
+	return ProbeResult{}, &Error{Code: ErrorUnavailable, Err: fmt.Errorf("real ONVIF adapter is not configured")}
+}
+
+func (UnavailableAdapter) SetSystemDateAndTime(context.Context, Target, time.Time) error {
+	return &Error{Code: ErrorUnavailable, Err: fmt.Errorf("real ONVIF adapter is not configured")}
+}