fuse without voltageRating renders a bare unit: "1A / V" on the schematic, "V" in circuit JSON

What happens

A <fuse /> without voltageRating renders a bare unit with no number — on the schematic symbol and in circuit JSON:

<fuse name="F1" currentRating="1A" footprint="0402" />

source_component.display_current_rating  "1A"
source_component.display_voltage_rating  "V"      ← no value
schematic_component.symbol_display_value "1A / V" ← rendered on the schematic

voltageRating is optional in the props schema (voltageRating?: number | string), while currentRating is required — a fuse without a currentRating fails validation outright (Invalid props for fuse "F4": currentRating (Required)). So "current only" is a fully supported, and probably common, way to declare a fuse, and it's the case that renders wrong.

Cause

lib/components/normal-components/Fuse.ts interpolates the formatted value unconditionally:

display_voltage_rating: `${formatSiUnit(voltageRating)}V`,
...
return `${formatSiUnit(current)}A / ${formatSiUnit(voltage)}V`

formatSiUnit(undefined) returns "", so the template collapses to just the unit suffix.

Prior art in this repo

Resonator._getSchematicSymbolDisplayValue() already handles exactly this shape correctly — it drops the optional half rather than emitting an empty unit:

const freqDisplay = `${formatSiUnit(this._parsedProps.frequency)}Hz`
if (this._parsedProps.loadCapacitance) {
  return `${freqDisplay} / ${formatSiUnit(this._parsedProps.loadCapacitance)}F`
}
return freqDisplay

Why no test catches it

tests/components/normal-components/fuse.test.tsx is the only fuse component test and it passes both ratings, so the optional-field path is never exercised.

Interestingly the repo already contains schematic snapshots showing the bug, they just weren't recognised as wrong:

• tests/features/schematic-text-bounding-box/schematic-text-bounding-box-fuse.test.tsx — four fuses, all currentRating="2A" with no voltage, all rendering 2A / V.
• schematic-section-rp2040.test.tsx and schematic-section-rp2040-autolayout.test.tsx — <fuse name="F1" currentRating="500mA" />, rendering 500mA / V.

Happy to submit a PR (already have one ready).

Start in lib/components/normal-components/Fuse.ts and compare its display formatting with Resonator. Run tests/components/normal-components/fuse.test.tsx, then inspect the mentioned schematic snapshot tests for the missing-voltage case. Done means a fuse with only currentRating no longer emits a bare V in schematic or circuit JSON, with regression coverage for the optional field.