Login had no visible entry point — you could only reach it by hitting a guard.
Add an auth footer the pages splice in: "log in" when logged out, "signed in
as <user> · log out" when logged in.
- host/auth-footer: SX fragment reading the session principal; guards a
session-less request so it's safe to call anywhere.
- GET /logout added alongside POST so the footer link is a plain <a> (logout
is low-harm; GET is acceptable). Clears the session, redirects home.
- home and post pages splice (host/auth-footer req) into their footer.
Tests: home + post footers show a login link when anonymous; GET /logout ->
303. 221/221. Verified live: anonymous shows "log in"; logged in shows
"signed in as admin · log out"; /logout reverts it.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>