controller v0.94.0: pull-based config-refresh (re-pull + self-restart on config_version change)

PushResponse.ConfigVersion from the report ACK; ConfigRefresher reconciles vs.
the last-applied version (settings.applied_config_version) and on a change calls
bootstrap.RefreshConfig (re-pull controller.yaml + re-merge local_api) then
GracefulSelfRestart. First-run records baseline (no restart); unchanged = no-op
(no storm); failed pull keeps config + retries. Companion to hub v0.26.0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HxLA1mZurFq9kt8hneFeCs

controller/internal/report/pusher.go

@@ -32,6 +32,11 @@ type PushResponse struct {
 	// "update to latest" button — never the auto-target).
 	MinControllerVersion string `json:"min_controller_version"`
 	LatestVersion        string `json:"latest_version"`
+	// ConfigVersion is the hub's per-customer config counter (v0.26.0). On a change vs. the
+	// last-applied version, the controller re-pulls controller.yaml + self-restarts (pull-based config
+	// delivery — the hub never connects into the box). 0 = the hub didn't advertise it (old hub, or a
+	// report-only customer with no config row) → the controller does nothing.
+	ConfigVersion int `json:"config_version"`
 }
 
 // Pusher sends reports to the central hub.