feat: icon+tooltip buttons on meal-plan/shopping-list headers (v0.28.0)

Match the recipe detail page's action-row convention: Share, Generate
shopping list, Shopping lists link, Print, Export to calendar, and
Send to grocery delivery collapse to icon-only with a tooltip instead
of icon+text, freeing up header space. Week prev/next arrows moved
next to the week date instead of sitting at the end of the button row.

Note: verified via typecheck/lint only — this dev environment has no
authenticated session to visually confirm in-browser.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/messages/en.json

@@ -856,6 +856,8 @@
     "markCookedSuccess": "Marked as cooked",
     "markCookedFailed": "Failed to mark as cooked",
     "exportCalendar": "Export to calendar",
+    "previousWeek": "Previous week",
+    "nextWeek": "Next week",
     "clearDay": "Clear day",
     "clearWeek": "Clear week",
     "clearDayConfirmTitle": "Clear {day}?",