Wraps the canvas root so every tenant-subdomain request checks for a
valid session and bounces to app.moleculesai.app/cp/auth/login with a
return_to pointing back at the current URL. Local dev + vercel preview
URLs + apex pass through unchanged.
Files:
- canvas/src/lib/auth.ts: fetchSession() probes /cp/auth/me
(credentials:include for cross-origin cookie); returns Session on 200,
null on 401 (anonymous, no throw), throws on 5xx so transient
outages don't leak the UI.
- canvas/src/lib/auth.ts: redirectToLogin() builds the cp login URL
with window.location.href as return_to; CP's isSafeReturnTo check
rejects cross-domain bounces.
- canvas/src/components/AuthGate.tsx: client component wrapping
children. State machine: loading → authenticated | anonymous. In
non-SaaS mode (no tenant slug) skips the gate entirely.
- canvas/src/app/layout.tsx: wraps the root body in <AuthGate>.
Tests: +6 auth.ts (200 / 401 null / 5xx throw / credentials:include /
redirectToLogin href + signup variant). Full suite 453 green (was 447).
Pairs with molecule-controlplane PR #16 (return_to cookie handshake
on the cp side).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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