docs: refresh documentation for the current API and fix formatting

[Bccorb]

What

A documentation freshness pass ahead of the 0.5.0 release, plus the formatting fix for two files that were already unformatted on main.

Formatting

• tsconfig.build.json and .changeset/dts-relative-paths.md were unformatted on main (merged without passing prettier), so main's own npm run format:check was red. Both are now formatted. The whole repo passes format:check.

Documentation accuracy

Reconciled the docs with everything that landed this cycle: the result convention across the client and provider, the route renames, the OTP and magic-link move to POST, email-only registration, and the type renames.

• README.md
  • "What It Exports" now names SeamlessAuthError and the SeamlessAuthResult wrapper
  • the custom registration recipe registers with an email only (was email plus phone), matching the bundled view
  • "Backend Expectations" marks the state-changing OTP and magic-link routes as POST, with a note on the CSRF reason and the adapter-version dependency
• AGENTS.md
  • the public API summary listed removed types (PasskeyLoginResult, PasskeyLoginWithPrfResult, PasskeyRegistrationResult, StepUpVerificationResult, StepUpWithPasskeyPrfResult); replaced with the current ones (PasskeyLoginData, PasskeyRegistrationData, StepUpPrfData, MessageResult, CredentialUpdateResult, OrganizationMembershipResult, OrganizationSwitchResult, SeamlessAuthResult) and SeamlessAuthError
  • added a line stating the SDK-wide result convention
  • the "rough edges" bullet claiming some methods return raw Response for the caller to check was removed, since that is no longer true
  • the backend-endpoints section marks the POST routes and explains the casing and method coupling to the adapter
• CONTRIBUTING.md
  • fixed the dev-server port (5137 was a transposition of 5173, contradicting two other lines in the same guide) and two typos (avaliable, integerate)
• RELEASES.md
  • added an "Adapter compatibility" section: some SDK changes require a matching @seamless-auth/express version, and when a change spans both repos the adapter publishes first. This is the gap that made the OTP and magic-link changes a coordination risk

SECURITY.md and LICENSE.md were reviewed and are accurate.

No changeset

Docs and build-config formatting only. The behaviors these docs describe already shipped with their own changesets, so there is no new adopter-facing change to record. The refreshed README will ship with the next publish as part of the repo state.

Timing note

Merge this before the release PR (#68) is finalized so 0.5.0 publishes with the corrected README. It does not need its own version bump.

Checks

• npm run format:check clean across the repo
• Full suite still green (223 passed); no source touched
• Every doc code snippet checked against the current exports: no reference to a removed or renamed API remains