merge feat/probe-b6: item 7 B1-B6 (probe collector, history, contract API, ping, themes, notify)

# Conflicts:
#	internal/agent/agent.go

internal/agent/agent.go

@@ -102,6 +102,10 @@ type Agent struct {
 	sbVer    string
 	sbVerFor string
 	sbVerMod time.Time
+
+	// Latency probe runner (item 7 B4, see ping.go): task set pushed
+	// on the config poll, samples returned on the heartbeat.
+	probes *probeRunner
 }
 
 // ensureSingboxState lazily creates the sing-box runtime state.
@@ -132,6 +136,7 @@ func New(cfg *Config) *Agent {
 			},
 		},
 		stopCh: make(chan struct{}),
+		probes: newProbeRunner(),
 	}
 }
 
@@ -150,9 +155,11 @@ func (e *statusError) Error() string {
 // Register registers the agent with the master
 func (a *Agent) Register() error {
 	url := fmt.Sprintf("%s/panel/api/agent/register", a.config.MasterURL)
-	payload := map[string]string{
+	payload := map[string]any{
 		"token": a.config.Token,
 		"name":  a.config.NodeName,
+		// Probe facts ride along (B1): old masters ignore the extra field.
+		"probeFacts": collectFacts(),
 	}
 	body, _ := json.Marshal(payload)
 	req, err := http.NewRequest("POST", url, bytes.NewReader(body))
@@ -291,6 +298,9 @@ func (a *Agent) Run() error {
 
 // Stop stops the agent
 func (a *Agent) Stop() {
+	if a.probes != nil {
+		a.probes.stop()
+	}
 	close(a.stopCh)
 }
 
@@ -313,13 +323,30 @@ func (a *Agent) sendHeartbeat() error {
 		"token":     a.config.Token,
 		"timestamp": time.Now().Unix(),
 		"telemetry": a.collectTelemetry(),
+		// Probe snapshot (B1): facts are process-cached so re-sending them
+		// costs nothing and heals a master that missed the register-time
+		// copy; metrics are sampled fresh each heartbeat. Old masters
+		// ignore both fields.
+		"probeFacts":   collectFacts(),
+		"probeMetrics": collectMetrics(),
 	}
 	if rep := a.currentUpdateReport(); rep != nil {
 		payload["updateStatus"] = rep
 	}
+	// Latency probe samples (B4) ride the heartbeat — deliberately not
+	// the traffic report, which stops when xray is down while probing
+	// must not. Drained here, requeued on any failure below.
+	var probeBatch []ProbeResult
+	if a.probes != nil {
+		probeBatch = a.probes.drainResults()
+		if len(probeBatch) > 0 {
+			payload["probeResults"] = probeBatch
+		}
+	}
 	body, _ := json.Marshal(payload)
 	req, err := http.NewRequest("POST", url, bytes.NewReader(body))
 	if err != nil {
+		a.requeueProbeBatch(probeBatch)
 		return err
 	}
 	req.Header.Set("Content-Type", "application/json")
@@ -327,15 +354,25 @@ func (a *Agent) sendHeartbeat() error {
 
 	resp, err := a.do(req)
 	if err != nil {
+		a.requeueProbeBatch(probeBatch)
 		return err
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode != http.StatusOK {
+		a.requeueProbeBatch(probeBatch)
 		return fmt.Errorf("heartbeat failed with status %d", resp.StatusCode)
 	}
 	return nil
 }
 
+// requeueProbeBatch returns a heartbeat's probe samples to the
+// runner buffer after a failed send.
+func (a *Agent) requeueProbeBatch(batch []ProbeResult) {
+	if a.probes != nil {
+		a.probes.requeueResults(batch)
+	}
+}
+
 // fetchAndApplyConfig fetches the xray config from master and applies it if changed
 func (a *Agent) fetchAndApplyConfig() error {
 	url := fmt.Sprintf("%s/panel/api/agent/config", a.config.MasterURL)
@@ -362,6 +399,11 @@ func (a *Agent) fetchAndApplyConfig() error {
 		SingboxConfig     json.RawMessage `json:"singbox_config"`
 		SingboxConfigHash string          `json:"singbox_config_hash"`
 		AgentUpdate       *updateIntent   `json:"agent_update"`
+		// ProbeTasks is a pointer on purpose (B4): a master too old
+		// to know probes omits the field and the agent must keep its
+		// current set, while a present-but-empty list means "run no
+		// probes" and clears it.
+		ProbeTasks *[]ProbeTask `json:"probe_tasks"`
 	}
 	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
 		return err
@@ -383,6 +425,12 @@ func (a *Agent) fetchAndApplyConfig() error {
 		}
 	}
 
+	// Probe tasks change independently of the xray config, so they
+	// are applied before the hash early-return below.
+	if result.ProbeTasks != nil && a.probes != nil {
+		a.probes.applyTasks(*result.ProbeTasks)
+	}
+
 	// Skip if config hasn't changed
 	if result.ConfigHash == a.lastConfigHash && result.ConfigHash != "" {
 		return nil