fix: key fuse connections on pin labels (#754)

[adityaaa-IIT-BHU]

Fixes #754

Problem

fuseProps accepted any string as a connections key, so a typo'd pin name passed validation silently:

const typo = { pin99: ".R1 > .pin1" }

fuseProps.safeParse({ name: "F1", currentRating: "1A", connections: typo })      // success ✅  ← wrong
capacitorProps.safeParse({ name: "C1", capacitance: "1uF", connections: typo })  // success ❌
resistorProps.safeParse({ name: "R1", resistance: "1k", connections: typo })     // success ❌

{ "not a pin at all": ... } and { "": ... } got through too. A fuse is a two-pin passive like a resistor or capacitor, so there's no reason for it to differ.

Cause

Two related gaps in lib/components/fuse.ts:

1. It hand-rolled the schema as z.record(z.string(), ...) instead of using the shared createConnectionsProp helper, which keys the record on z.enum(labels) so unknown keys fail. fusePinLabels was already defined and exported in the file — it just wasn't used here.

2. Nothing checked the schema against the interface. FuseProps declared connections?: Connections<PinLabel> while the schema produced Record<string, ...>. Fuse was the only component in lib/components/ that exported both an interface and an Inferred* type without calling expectTypesMatch, which is why the two were able to drift.

Change

• connections: createConnectionsProp(fusePinLabels).optional()
• Narrow the interface to Connections<FusePinLabels>, matching capacitor.ts and resistor.ts
• Add expectTypesMatch<FuseProps, InferredFuseProps>(true) so this can't drift again

This is the idiom AGENTS.md already calls for: "Electrical connectivity should usually be connections keyed by known pin labels."

Adding the assertion to the unfixed file fails, confirming the drift was real:

error TS2345: Argument of type 'true' is not assignable to parameter of
type '"property connections has mismatched types"'.

Behaviour

connections	before	after
{ pin1: "net.VCC", pin2: ["net.GND"] }	accepted	accepted (unchanged)
{ pin99: "..." }	accepted	rejected
{ "not a pin at all": "..." }	accepted	rejected
{ "": "..." }	accepted	rejected
omitted	undefined	undefined (unchanged)

Valid fuse connections parse to exactly the same value as before, so no real circuit changes behaviour.

Generated docs were refreshed per AGENTS.md (generate-component-types, generate-manual-edits-docs, generate-readme-docs, generate-props-overview); the only diffs are the fuse sections.

Verification

• bun test — 416 pass / 0 fail (was 412; +4 new tests in tests/fuse.test.ts)
• bunx tsc --noEmit — clean (this is what exercises the new expectTypesMatch)
• bun run format:check — clean
• git diff --check — clean