fix(shopping): stale-row cleanup, cache-busting, view persistence

Root cause of the doubled lists: the relay DB had stale rows from
previous activations that were never deleted. The composite PK
prevented same-uid duplicates but not leftover rows from cards that
were deactivated without a successful DELETE.

Fixes:
  - Client tick sends DELETE { keep: [active uids] } after every
    push cycle. The relay drops all rows for this tenant that aren't
    in the keep list — cleans up migration leftovers, failed deletes,
    old single-list sentinels, everything in one shot.
  - Relay DELETE endpoint accepts { keep: [...] } for bulk cleanup
    alongside the existing { card_uid } single-delete.
  - Relay layout.php adds cache-busting query strings on style.css
    and app.js via filemtime() so phone browsers pick up new code
    on deploy instead of serving stale cached versions.
  - showView persists the active view name to localStorage; after
    login the relay restores it instead of always landing on compose.
  - Shopping-list-box border/background removed — items have their
    own chrome, the box is just a flex grouper now.
  - View title is always "Shopping"; each list box keeps its own
    header with the card title. No more doubled name.

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

relay/ui/app.js

@@ -112,6 +112,11 @@ function showView(name) {
     } else {
         stopShoppingPoll();
     }
+    // Remember the active view so a page reload lands back here
+    // instead of defaulting to compose every time.
+    if (['compose', 'account', 'admin', 'chat', 'shopping'].includes(name)) {
+        try { localStorage.setItem('relay-last-view', name); } catch {}
+    }
     if (name === 'admin') {
         loadUsers();
     } else if (name === 'account') {
@@ -279,7 +284,8 @@ function routePostLogin(status) {
         showView('account');
         toast('set your client secret to start using the relay');
     } else {
-        showView('compose');
+        const last = localStorage.getItem('relay-last-view') || 'compose';
+        showView(['compose', 'account', 'admin', 'chat', 'shopping'].includes(last) ? last : 'compose');
     }
 }
 
@@ -786,7 +792,7 @@ async function loadShopping(quiet = false) {
         list.innerHTML = '<li class="empty">no active shopping lists</li>';
         return;
     }
-    if (title) title.textContent = lists.length === 1 ? (lists[0].title || 'Shopping') : 'Shopping';
+    if (title) title.textContent = 'Shopping';
     list.innerHTML = '';
     for (const entry of lists) {
         const nodes = shoppingParseLines(entry.body);
@@ -794,12 +800,10 @@ async function loadShopping(quiet = false) {
         // List box wrapper
         const box = document.createElement('li');
         box.className = 'shopping-list-box';
-        if (lists.length > 1 || entry.title) {
-            const hdr = document.createElement('div');
-            hdr.className = 'shopping-list-header';
-            hdr.textContent = entry.title || '(untitled)';
-            box.appendChild(hdr);
-        }
+        const hdr = document.createElement('div');
+        hdr.className = 'shopping-list-header';
+        hdr.textContent = entry.title || '(untitled)';
+        box.appendChild(hdr);
         if (!hasItems) {
             const done = document.createElement('div');
             done.className = 'shopping-list-done';