feat(v2): add annotated evidence and alert dispatch

v2/internal/alert/dispatcher_test.go

@@ -0,0 +1,57 @@
+package alert
+
+import (
+	"image"
+	"image/color"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"silverpose/v2/internal/fall"
+)
+
+func TestDispatchWritesOnePNGAndRedactedJSONL(t *testing.T) {
+	dispatcher := NewDispatcher(t.TempDir(), "lobby-camera-01")
+	event := fall.Event{
+		EventID: "FALL-run-000001", TrackID: "P-0001", ConfigVersion: "cfg-safe",
+		SuspectedAtMonotonic: 10, ConfirmedAtMonotonic: 11.8, LatencySeconds: 1.8, State: fall.Confirmed,
+	}
+	canvas := image.NewRGBA(image.Rect(0, 0, 2, 2))
+	canvas.SetRGBA(0, 0, color.RGBA{R: 1, G: 2, B: 3, A: 255})
+	now := time.Date(2026, 7, 22, 8, 0, 0, 0, time.UTC)
+
+	first, err := dispatcher.Dispatch(event, canvas, now)
+	if err != nil || !first.Written {
+		t.Fatalf("first dispatch = %#v, %v", first, err)
+	}
+	second, err := dispatcher.Dispatch(event, canvas, now)
+	if err != nil || second.Written {
+		t.Fatalf("duplicate dispatch = %#v, %v", second, err)
+	}
+	if extension := filepath.Ext(first.ScreenshotPath); extension != ".png" {
+		t.Fatalf("screenshot extension = %q", extension)
+	}
+	if _, err := os.Stat(first.ScreenshotPath); err != nil {
+		t.Fatal(err)
+	}
+	jsonl, err := os.ReadFile(first.LogPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if lines := strings.Count(strings.TrimSpace(string(jsonl)), "\n") + 1; lines != 1 {
+		t.Fatalf("JSONL lines = %d: %s", lines, jsonl)
+	}
+	if strings.Contains(string(jsonl), "rtsp") || strings.Contains(string(jsonl), "secret") {
+		t.Fatalf("JSONL leaked source details: %s", jsonl)
+	}
+}
+
+func TestDispatchRejectsNonConfirmedEvent(t *testing.T) {
+	dispatcher := NewDispatcher(t.TempDir(), "lobby-camera-01")
+	_, err := dispatcher.Dispatch(fall.Event{EventID: "FALL-run-000001", State: fall.Suspect}, image.NewRGBA(image.Rect(0, 0, 1, 1)), time.Now())
+	if err == nil {
+		t.Fatal("expected non-confirmed event error")
+	}
+}