feat(join): implement A4 join household page (/join/[token])
- schema.d.ts: add GET /v1/invites/{code}, InviteInfoResponse, AcceptInviteRequest; update acceptInvite operation
- hooks.server.ts: add /join to PUBLIC_ROUTES; redirect authenticated users on /join/* to /
- +page.server.ts: load validates token (invalid:true on 404); action creates account + joins + sets session cookie
- HouseholdIdentityPanel.svelte: logo, household name (Fraunces), inviter text, static permissions list
- JoinForm.svelte: name/email/password + show/hide toggle, "Haushalt beitreten" CTA, field errors, pre-fill
- +page.svelte: no-chrome layout, mobile (banner+form stacked) / desktop (400px panel + flex:1) split, invalid-token inline state
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Marcel Raddatz
6950b3d8db