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/runner/blender/version_test.go

@@ -0,0 +1,10 @@
+package blender
+
+import "testing"
+
+func TestVersionString(t *testing.T) {
+	if got := VersionString(4, 2); got != "4.2" {
+		t.Fatalf("VersionString() = %q, want %q", got, "4.2")
+	}
+}
+