WIDGETS: synth-smells

Part of #1377.

Problem

Drop a yosys log: inferred latches, undriven wires, memories turned into registers, removed cells. A shareable lint card from your own synthesis.

specs/widgets/synth-smells.t27 (KIND widget-tool) with >= 2 passing tests; every number from a named real run.
Works at 375px and in a 640x460 ?embed=1 iframe; the reader's file never leaves the browser.
tri widget status shows it complete.