init: tianyan-edge edge agent with Ascend NPU inference backend

- Go main process: stream ingestor, infer client, event uploader,
  heartbeat, config agent, OTA agent
- Python inference server rewritten to use CANN ACL (acl module)
  replacing ultralytics/PyTorch; supports YOLOv8 raw and YOLOv10
  NMS-free output formats via OUTPUT_FORMAT env var
- systemd services for edge-agent and edge-infer
- build/install/package scripts targeting arm64

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

internal/stream/ingestor.go

@@ -0,0 +1,129 @@
+package stream
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"os/exec"
+	"sync"
+	"time"
+
+	"tianyan-edge/internal/config"
+)
+
+type Frame struct {
+	StreamID int
+	DeviceID string
+	URL      string
+	JPEG     []byte
+	TS       float64
+}
+
+type Ingestor struct {
+	cfg    *config.Config
+	frames chan<- Frame
+}
+
+func NewIngestor(cfg *config.Config, frames chan<- Frame) *Ingestor {
+	return &Ingestor{cfg: cfg, frames: frames}
+}
+
+func (ing *Ingestor) Run(ctx context.Context) {
+	if len(ing.cfg.RTSPURLs) == 0 {
+		log.Println("stream: no RTSP URLs configured, idle")
+		<-ctx.Done()
+		return
+	}
+	var wg sync.WaitGroup
+	for i, url := range ing.cfg.RTSPURLs {
+		wg.Add(1)
+		go func(idx int, u string) {
+			defer wg.Done()
+			ing.streamLoop(ctx, idx, u)
+		}(i, url)
+	}
+	wg.Wait()
+}
+
+func (ing *Ingestor) streamLoop(ctx context.Context, idx int, url string) {
+	deviceID := fmt.Sprintf("cam-%03d", idx)
+	fps := ing.cfg.InferFPS
+	if fps <= 0 {
+		fps = 5
+	}
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
+		cmd := exec.CommandContext(ctx, "ffmpeg",
+			"-rtsp_transport", "tcp", "-i", url,
+			"-vf", fmt.Sprintf("fps=%d", fps),
+			"-f", "image2pipe", "-vcodec", "mjpeg", "-q:v", "5", "-",
+		)
+		stdout, err := cmd.StdoutPipe()
+		if err != nil {
+			log.Printf("stream[%d] stdout pipe failed: %v, retry 10s", idx, err)
+			time.Sleep(10 * time.Second)
+			continue
+		}
+		if err := cmd.Start(); err != nil {
+			log.Printf("stream[%d] ffmpeg start failed: %v, retry 10s", idx, err)
+			time.Sleep(10 * time.Second)
+			continue
+		}
+		log.Printf("stream[%d] connected  url=%s", idx, url)
+		ing.readFrames(ctx, stdout, idx, deviceID, url)
+		cmd.Wait()
+		select {
+		case <-ctx.Done():
+			return
+		default:
+			log.Printf("stream[%d] lost, retry 5s", idx)
+			time.Sleep(5 * time.Second)
+		}
+	}
+}
+
+func (ing *Ingestor) readFrames(ctx context.Context, r io.Reader, idx int, deviceID, url string) {
+	soi, eoi := []byte{0xFF, 0xD8}, []byte{0xFF, 0xD9}
+	buf, tmp := make([]byte, 0, 1<<20), make([]byte, 32768)
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
+		n, err := r.Read(tmp)
+		if n > 0 {
+			buf = append(buf, tmp[:n]...)
+			for {
+				s := bytes.Index(buf, soi)
+				if s < 0 {
+					buf = buf[:0]
+					break
+				}
+				buf = buf[s:]
+				e := bytes.Index(buf[2:], eoi)
+				if e < 0 {
+					break
+				}
+				end := e + 4
+				frame := make([]byte, end)
+				copy(frame, buf[:end])
+				buf = buf[end:]
+				select {
+				case ing.frames <- Frame{StreamID: idx, DeviceID: deviceID, URL: url,
+					JPEG: frame, TS: float64(time.Now().UnixMilli()) / 1000.0}:
+				default:
+				}
+			}
+		}
+		if err != nil {
+			return
+		}
+	}
+}