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>

relay/ui/style.css

@@ -232,13 +232,8 @@ label.checkbox input[type="checkbox"] { accent-color:var(--accent); cursor:point
 #view-compose:not(.hidden) {
     display: flex; flex-direction: column; gap: 16px;
 }
-/* Same 16 px rhythm between inbox / shared / sent on mobile as
-   between compose and inbox — desktop re-declares this inside the
-   grid rule further down. */
-#compose-sidebar {
-    display: flex;
-    flex-direction: column;
-    gap: 16px;
+#view-inbox:not(.hidden) {
+    display: flex; flex-direction: column; gap: 16px;
 }
 .compose-attachments {
     display: flex; flex-wrap: wrap; gap: 6px; min-height: 0;
@@ -677,23 +672,28 @@ header .nav-btn .ph { font-size:11px; vertical-align:-1px; margin-right:2px; }
         display:flex !important;
         flex-direction:column;
         align-items:stretch;
-        position:absolute;
-        top:100%;
-        right:12px;
-        margin-top:6px;
+        position:fixed;
+        top: 48px;
+        left: 0;
+        right: 0;
+        bottom: 0;
+        margin: 0;
         background:var(--surface);
-        border:1px solid var(--border);
-        border-radius:var(--radius-lg);
-        box-shadow: var(--shadow-popover);
-        padding:6px;
-        gap:4px;
-        min-width:180px;
-        z-index:50;
+        border-top:1px solid var(--border);
+        border-radius: 0;
+        padding: 12px 16px;
+        gap: 6px;
+        z-index:100;
     }
     #nav-buttons.menu-open .nav-btn {
         text-align:left;
         width:100%;
-        padding: 8px 12px;
+        padding: 14px 16px;
+        font-size: 15px;
+    }
+    #nav-buttons.menu-open .nav-btn .ph {
+        font-size: 16px;
+        margin-right: 8px;
     }
 
     #view-admin .section {
@@ -757,18 +757,11 @@ header .nav-btn .ph { font-size:11px; vertical-align:-1px; margin-right:2px; }
         border-radius: var(--radius);
     }
 
-    /* Compose view: 2 columns. Left is the compose editor. Right is a
-       sidebar with inbox → shared → sent stacked vertically. */
+    /* Compose view: single column, centered. Inbox/shared/sent are in
+       their own view now — no sidebar to fill the right-hand space. */
     #view-compose:not(.hidden) {
-        display: grid !important;
-        grid-template-columns: minmax(0, 1.7fr) minmax(0, 1fr);
-        gap: 24px;
-        align-items: start;
-    }
-    #compose-sidebar {
-        display: flex;
-        flex-direction: column;
-        gap: 16px;
+        max-width: 720px;
+        margin: 0 auto;
     }
 
     /* Cards: depth via shadow + larger padding */
@@ -810,18 +803,6 @@ header .nav-btn .ph { font-size:11px; vertical-align:-1px; margin-right:2px; }
         font-size: 12px;
     }
 
-    /* Inbox card sticks under the header */
-    #inbox-section {
-        position: sticky;
-        top: 24px;
-        transition: box-shadow .15s;
-    }
-    #inbox-section:hover {
-        box-shadow:
-            0 1px 2px rgba(0,0,0,0.3),
-            0 12px 32px -8px rgba(0,0,0,0.5),
-            0 0 0 1px color-mix(in srgb, var(--accent) 20%, transparent);
-    }
 
     /* Admin: 2-column grid */
     #view-admin:not(.hidden) .section {