v0.3.0: fix HTTP client leak, add tests and CI pipeline

Reuse a single long-poll HTTP client instead of creating one per
Events() call (~every 30s). Make TLS skip-verify configurable via
syncthing_insecure_tls. Log previously swallowed config errors.
Add unit tests for all monitor trackers, config, and state logic.
Add CI workflow (vet, golangci-lint, govulncheck, go test -race).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/monitor/folders_test.go

@@ -0,0 +1,67 @@
+package monitor
+
+import (
+	"testing"
+
+	st "git.davoryn.de/calic/syncwarden/internal/syncthing"
+)
+
+func TestFolderTracker_UpdateFromConfig(t *testing.T) {
+	ft := NewFolderTracker()
+	ft.UpdateFromConfig([]st.FolderConfig{
+		{ID: "docs", Label: "Documents", Path: "/home/user/docs"},
+		{ID: "photos", Label: "Photos", Path: "/home/user/photos"},
+	})
+
+	folders := ft.Folders()
+	if len(folders) != 2 {
+		t.Fatalf("expected 2 folders, got %d", len(folders))
+	}
+	if folders[0].Label != "Documents" {
+		t.Errorf("expected label 'Documents', got %q", folders[0].Label)
+	}
+	if folders[0].State != "unknown" {
+		t.Errorf("initial state should be 'unknown', got %q", folders[0].State)
+	}
+}
+
+func TestFolderTracker_EmptyLabelFallback(t *testing.T) {
+	ft := NewFolderTracker()
+	ft.UpdateFromConfig([]st.FolderConfig{
+		{ID: "my-folder", Label: "", Path: "/data"},
+	})
+
+	folders := ft.Folders()
+	if folders[0].Label != "my-folder" {
+		t.Errorf("empty label should fall back to ID, got %q", folders[0].Label)
+	}
+}
+
+func TestFolderTracker_UpdateStatus(t *testing.T) {
+	ft := NewFolderTracker()
+	ft.UpdateFromConfig([]st.FolderConfig{
+		{ID: "docs", Label: "Docs", Path: "/docs"},
+	})
+
+	ft.UpdateStatus("docs", "syncing")
+
+	folders := ft.Folders()
+	if folders[0].State != "syncing" {
+		t.Errorf("expected 'syncing', got %q", folders[0].State)
+	}
+}
+
+func TestFolderTracker_UpdateStatusNonexistent(t *testing.T) {
+	ft := NewFolderTracker()
+	ft.UpdateFromConfig([]st.FolderConfig{
+		{ID: "docs", Label: "Docs", Path: "/docs"},
+	})
+
+	// Should not panic
+	ft.UpdateStatus("nonexistent", "idle")
+
+	folders := ft.Folders()
+	if folders[0].State != "unknown" {
+		t.Errorf("existing folder should be unchanged, got %q", folders[0].State)
+	}
+}