fix(webauthn): advertise every algorithm the FIDO specification requires

[Bccorb]

Closes #166. No cross-repo work, no release round trip.

The gap

generateRegistrationOptions never set supportedAlgorithmIDs, so the
SimpleWebAuthn default applied:

const defaultSupportedAlgorithmIDs = [-8, -7, -257];  // EdDSA, ES256, RS256

FIDO Server Requirements v2.3 requires a server to implement RS1, RS256,
ES256 and EdDSA. RS1 was missing, and a conformance run would have flagged
it.

Ordering is part of the fix, not decoration

pubKeyCredParams is an ordered preference list, so where RS1 sits matters
as much as whether it is there. RS1 is RSASSA-PKCS1-v1_5 with SHA-1:

const SUPPORTED_ALGORITHM_IDS = [
  -8,     // EdDSA
  -7,     // ES256
  -257,   // RS256
  -65535, // RS1
];

Advertised because the specification requires support for it, ordered last so no
authenticator with a better option available will choose it. Both facts are
asserted, including a separate assertion that RS1 is specifically the last entry
rather than merely present.

A second gap found while fixing the first

verifyRegistrationResponse takes the same option, and its default is every
algorithm the library knows. So the server was accepting credentials using
algorithms it never advertised. Verification is now pinned to the same constant,
so what is offered and what is accepted cannot drift apart.

Why state the set at all

Leaving it to a library default means a minor upgrade can silently change what
this server advertises. That is how RS1 came to be missing in the first place.
The test pins the exact array, so the next upgrade that changes it fails loudly.

Mutation checked

Removing RS1 from the constant fails exactly the two new tests and nothing else,
so they are real guards rather than assertions that happen to pass.

Verification

92 test files, 1012 passed, 1 skipped. Coverage 98.78% lines. typecheck,
lint, format:check clean. Contract regenerated, no change to it: the
algorithm set is inside the generated credential options rather than in the
documented schema.