relay UI overhaul, favicon, settings, admin last-seen, fixes

Relay:
  - Inbox/shared/sent split into own view-inbox (nav button + poll).
    Compose is now single-column, centered.
  - Header logo links to compose. Inbox badge stays fresh on all
    views via a quiet loadInbox on every view switch.
  - Mobile menu: full-height sheet below header, larger buttons
    (15px font, 14px padding), full width.
  - Login form wrapped in <form> with name attributes + for/id on
    labels so password managers can autofill.
  - Admin user list shows "last seen <relative time>" per user.
    last_seen_at column on tenants, updated on every authenticated
    request (session + client API).
  - Cache-busting on style.css + app.js via filemtime.
  - View persistence in localStorage (survives reload).
  - Shared-bucket cards show title only (preview line removed).

Favicon:
  - favicon.svg added to project root + copied to public/, relay/,
    website/. Linked via <link rel="icon" type="image/svg+xml"> in
    all three <head> sections.

Settings:
  - New toggle: "Show shopping list items in task collector"
    (default off). collectTasks skips #einkauf/#shopping cards when
    disabled.

Fixes:
  - card-spinner gets display:inline-block so it rotates outside
    flex containers (shopping save spinner).
  - Tim tab test opens the plugin before checking active state.
  - Compose view centered with margin:auto on desktop.

Bumps to 1.9.29.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

website/index.html

@@ -4,6 +4,7 @@
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>hyprcrd</title>
+<link rel="icon" type="image/svg+xml" href="favicon.svg">
 <meta name="description" content="Self-hosted card manager. Markdown, tags, wiki-links, calendar, encrypted relay. Find everything.">
 <link rel="preconnect" href="https://fonts.googleapis.com">
 <link href="https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;700&family=Silkscreen&display=swap" rel="stylesheet">