Add tests for main package, manager, and various components

- Introduced unit tests for the main package to ensure compilation.
- Added tests for the manager, including validation of upload sessions and handling of Blender binary paths.
- Implemented tests for job token generation and validation, ensuring security and integrity.
- Created tests for configuration management and database schema to verify functionality.
- Added tests for logger and runner components to enhance overall test coverage and reliability.

internal/auth/secrets_test.go

@@ -0,0 +1,32 @@
+package auth
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestGenerateSecret_Length(t *testing.T) {
+	secret, err := generateSecret(8)
+	if err != nil {
+		t.Fatalf("generateSecret failed: %v", err)
+	}
+	// hex encoding doubles length
+	if len(secret) != 16 {
+		t.Fatalf("unexpected secret length: %d", len(secret))
+	}
+}
+
+func TestGenerateAPIKey_Format(t *testing.T) {
+	s := &Secrets{}
+	key, err := s.generateAPIKey()
+	if err != nil {
+		t.Fatalf("generateAPIKey failed: %v", err)
+	}
+	if !strings.HasPrefix(key, "jk_r") {
+		t.Fatalf("unexpected key prefix: %q", key)
+	}
+	if !strings.Contains(key, "_") {
+		t.Fatalf("unexpected key format: %q", key)
+	}
+}
+