fix(upgrade): break auto-apply restart loop (0.9.8)

Two bugs in 0.9.6/0.9.7 caused an infinite restart loop after a Force update
signal: the CLI never reported the upgrade outcome, so `upgrade_requested`
stayed `true`; AND `applyAutoUpgrade` called `os.Exit(0)` even when the
target version equalled the current one, so systemd respawned and saw the
flag again.

  - new Client.ReportUpgradeResult → POST /api/internal/agent/upgrade-result
  - applyAutoUpgrade calls it on success / failure / no-op
  - no-op case detected up front (same version) — skips Execute + Exit,
    clears server flag instead

internal/agent/client.go

@@ -91,6 +91,24 @@ func (c *Client) Deregister(ctx context.Context, agentID string) error {
 	return nil
 }
 
+// ReportUpgradeResult tells the server the outcome of a previously requested
+// upgrade so the server can clear `upgrade_requested`. Without this call the
+// flag stays sticky and the daemon would re-trigger applyAutoUpgrade on every
+// sync after upgrade — even for "already on target version" no-ops.
+func (c *Client) ReportUpgradeResult(ctx context.Context, agentID string, success bool, version, errMsg string) error {
+	req := struct {
+		AgentID string `json:"agentId"`
+		Success bool   `json:"success"`
+		Version string `json:"version,omitempty"`
+		Error   string `json:"error,omitempty"`
+	}{AgentID: agentID, Success: success, Version: version, Error: errMsg}
+	var resp StatusResponse
+	if err := c.doPost(ctx, "/api/internal/agent/upgrade-result", req, &resp); err != nil {
+		return fmt.Errorf("report upgrade result: %w", err)
+	}
+	return nil
+}
+
 // ReportStatus reports download progress. Returns server-side flags the CLI must act on.
 func (c *Client) ReportStatus(ctx context.Context, update StatusUpdate) (*StatusResponse, error) {
 	var resp StatusResponse

internal/agent/daemon.go

@@ -294,8 +294,30 @@ func (d *Daemon) Deregister() {
 // supervisor (systemd Restart=always on Linux) respawns on the new binary.
 // Triggered by the server's upgrade signal — opt-in flag set by the user from
 // the web UI; the daemon never auto-upgrades on a passive version bump.
+//
+// Reports the outcome to /api/internal/agent/upgrade-result so the server
+// clears `upgrade_requested`. Without this report the flag stays sticky and
+// the daemon would loop on every sync — including the no-op case where it's
+// already on the target version.
 func (d *Daemon) applyAutoUpgrade(targetVersion string) {
 	currentClean := strings.TrimPrefix(d.cfg.Version, "v")
+	targetClean := strings.TrimPrefix(targetVersion, "v")
+
+	// No-op: server signal arrived but we're already running the target. This
+	// happens when the daemon restarts after a previous auto-upgrade before
+	// reportUpgradeResult cleared the flag, or when the operator manually
+	// installed the same version off-band. Skip Execute (which would also
+	// no-op) AND skip os.Exit, but DO clear the flag — otherwise we loop.
+	if currentClean == targetClean {
+		log.Printf("[upgrade] already on v%s — clearing server flag", currentClean)
+		ctxR, cancelR := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancelR()
+		if err := d.client.ReportUpgradeResult(ctxR, d.cfg.AgentID, true, currentClean, ""); err != nil {
+			log.Printf("[upgrade] report-result failed (will retry on next signal): %v", err)
+		}
+		return
+	}
+
 	upgrader := &upgrade.Upgrader{
 		CurrentVersion: currentClean,
 		OnProgress: func(msg string) {
@@ -307,10 +329,24 @@ func (d *Daemon) applyAutoUpgrade(targetVersion string) {
 	result := upgrader.Execute(ctx, targetVersion)
 	if !result.Success {
 		log.Printf("[upgrade] auto-upgrade failed: %v", result.Error)
+		errMsg := ""
+		if result.Error != nil {
+			errMsg = result.Error.Error()
+		}
+		ctxR, cancelR := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancelR()
+		if err := d.client.ReportUpgradeResult(ctxR, d.cfg.AgentID, false, targetClean, errMsg); err != nil {
+			log.Printf("[upgrade] report-result failed: %v", err)
+		}
 		return
 	}
-	log.Printf("[upgrade] upgraded v%s → v%s; exiting so service supervisor restarts on new binary",
+	log.Printf("[upgrade] upgraded v%s → v%s; reporting result + exiting so service supervisor restarts on new binary",
 		result.OldVersion, result.NewVersion)
+	ctxR, cancelR := context.WithTimeout(context.Background(), 10*time.Second)
+	if err := d.client.ReportUpgradeResult(ctxR, d.cfg.AgentID, true, result.NewVersion, ""); err != nil {
+		log.Printf("[upgrade] report-result failed: %v", err)
+	}
+	cancelR()
 	time.Sleep(500 * time.Millisecond)
 	os.Exit(0)
 }