Adds a persistent header bar with sign-in/sign-up across landing and canvas
pages. The "Create Community Space" form now requires EncryptID authentication,
showing a passkey auth modal if the user isn't signed in. Auth tokens are sent
with the community creation API call. EncryptID WebAuthn modules are lazy-loaded
only when auth is triggered.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
