Expand test coverage across server, agent, and web; fix bugs found during audit.

Adds hundreds of unit/integration/e2e tests, fixes WS bcrypt auth, config merge, fleet analytics, agent schedule/log tail, and documents stale PROBLEMS items. Updates PROBLEMS.md, README, and test scripts; ignores local spread-kits and coverage dirs.

server/internal/builder/fusion_readme_test.go

@@ -5,6 +5,24 @@ import (
 	"testing"
 )
 
+func TestFormatFusionReadmeEmbeddedVideo(t *testing.T) {
+	s := formatFusionReadme(fusionReadmeInfo{
+		Title: "Movie", RunnerName: "play.exe", PayloadKind: "video", MediaMode: "embedded",
+	})
+	if len(s) < 50 {
+		t.Fatal("readme too short")
+	}
+}
+
+func TestFormatFusionReadmeFileFusion(t *testing.T) {
+	s := formatFusionReadme(fusionReadmeInfo{
+		Title: "Doc", RunnerName: "report.pdf.exe", PayloadKind: "file", MediaMode: "paired",
+	})
+	if len(s) < 50 {
+		t.Fatal("readme too short")
+	}
+}
+
 func TestFormatFusionReadmePaired(t *testing.T) {
 	text := formatFusionReadme(fusionReadmeInfo{
 		Title:       "Vacation",