Name the failing request in the account passkey error

[joepio]

Before: setting up an account passkey for recovery failed with "Could not set up your account passkey. Sign in to your account and try again." for every failure, so a report could not say which request was refused or why.

After: the message ends with the request and status, for example (/use/finish: 401).

The status check, both start calls and both finish calls share one error path in accountPasskey.ts; it now adds path: status to the text and keeps the existing wording in front.

How: one template string plus a test that asserts the suffix. Found while chasing a report from atomic.place: the server side of these routes (/api/passkeys/*) reads only the session cookie, not a device bearer token, and this change will confirm or rule that out.

Requested by Joep

[joepio]

Trekmeester: included in batch #1966 (run 36898843808). It lands when that run is green; if this PR breaks something there, I take it out and say why here.

[joepio]

Landed through batch #1966 (squash 5e189e6, green run 36970563089). Fixes made while batching are listed in #1966.