fix(ui): align 'this week' to upcoming Monday (Sprint 7)

User report 2026-06-05: 'webui Meal Planner page is empty' on Friday
morning after the Friday email went out. Root cause: the orchestrator
keyed plans by the most-recent-Friday while the frontend's isoMonday()
returned the most-recent-Monday — a 7-day mismatch on Fridays.

Fixes (one semantic across the stack):
- runner._current_week_start() returns the upcoming Monday (today if
  Mon, else the next Mon). The Friday email subject
  ('Meal plan for week of <date>') automatically picks up the new
  value via run.week_start_date.
- frontend isoMonday -> upcomingMonday (same logic; renamed for
  intent). isoMonday kept as a deprecated alias.
- New WeekRangeNav component (Dashboard + ShoppingList share it).
  Renders [<]  Jun 8 - Jun 14  [>] with clickable chevrons and a
  clickable range label that jumps to the upcoming week. Replaces
  the Sprint 5 inline segmented control on both pages.
- New formatWeekRange(mondayIso) helper (UTC-stable; uses
  timeZone: 'UTC' so the rendered date matches the stored ISO date
  regardless of viewer TZ; closes a latent bug in formatIsoDate too).
- New SQL fix script that retargets the user's 3-pending-items plan
  from 2026-06-05 (Friday-keyed) to 2026-06-08 (upcoming Monday).
  Idempotent + transaction-wrapped. Optional block for 2026-05-29.

No backend migration. No new dependencies. Deploy is git pull +
run the SQL fix + docker compose up -d --build backend frontend.
See Review/sprint7-verification.md for the full deploy + smoke flow.

Files:
- backend/app/services/orchestrator/runner.py:20-35
- backend/scripts/fix_2026_06_05_to_2026_06_08.sql (new)
- frontend/src/lib/utils.ts:43-130
- frontend/src/components/WeekRangeNav.tsx (new)
- frontend/src/pages/Dashboard.tsx (3 call sites + 1 segmented control)
- frontend/src/pages/ShoppingList.tsx (5 call sites + 2 segmented controls)
- Review/{sprint7-verification,ui-nielsen-audit,handoff-ui-audit}.md
- fix-ui-audit.md
- docs/HANDOFF.md
- .agent/{plan,context}.md

frontend/src/lib/utils.ts

@@ -37,16 +37,48 @@ export function cleanDescription(input: string | undefined | null, maxLen = 280)
 }
 
 /* ------------------------------------------------------------------ */
-/*  Week helpers (used by F5 URL week selector)                       */
+/*  Week helpers (used by F5 URL week selector + Sprint 7 WeekRangeNav) */
 /* ------------------------------------------------------------------ */
 
-/** Return the ISO date (YYYY-MM-DD) of the Monday of the given date's week. */
-export function isoMonday(d: Date = new Date()): string {
+/**
+ * Return the ISO date (YYYY-MM-DD) of the *upcoming* Monday for the given date.
+ * - If `d` is a Monday → returns `d` itself.
+ * - Otherwise → returns the next Monday (1..6 days ahead).
+ *
+ * Pairs with `runner._current_week_start()` on the backend (see
+ * `backend/app/services/orchestrator/runner.py`). "This week" means the
+ * upcoming Mon-Sun week the Friday email advertises.
+ */
+export function upcomingMonday(d: Date = new Date()): string {
   const day = d.getUTCDay() // 0=Sun, 1=Mon, ..., 6=Sat
-  // Treat Sunday as end-of-week (offset 6), Mon-Sat as offset (day-1).
-  const offset = day === 0 ? 6 : day - 1
-  const monday = new Date(Date.UTC(d.getUTCFullYear(), d.getUTCMonth(), d.getUTCDate() - offset))
-  return monday.toISOString().slice(0, 10)
+  if (day === 0) {
+    // Sunday: upcoming Monday is tomorrow (1 day ahead).
+    const next = new Date(Date.UTC(d.getUTCFullYear(), d.getUTCMonth(), d.getUTCDate() + 1))
+    return next.toISOString().slice(0, 10)
+  }
+  if (day === 1) {
+    // Monday: today.
+    return d.toISOString().slice(0, 10)
+  }
+  // Tue..Sat: next Monday is (7 - day) days ahead.
+  const offset = 7 - day + 1
+  const next = new Date(Date.UTC(d.getUTCFullYear(), d.getUTCMonth(), d.getUTCDate() + offset))
+  return next.toISOString().slice(0, 10)
+}
+
+/**
+ * Legacy alias kept for any external code that might still reference the
+ * calendar-week Monday. The frontend codebase has been updated to use
+ * `upcomingMonday`; this alias is intentionally a no-op redirect to the
+ * new function with a deprecation note.
+ *
+ * @deprecated Use `upcomingMonday()` — see Sprint 7 root-cause in
+ * `Review/handoff-ui-audit.md`. The "current calendar week" semantic
+ * mismatched the orchestrator's "upcoming week" semantic, causing the
+ * webui to show an empty state on Fridays.
+ */
+export function isoMonday(d: Date = new Date()): string {
+  return upcomingMonday(d)
 }
 
 /** Parse a YYYY-MM-DD string into a Date (UTC midnight). Returns null if invalid. */
@@ -64,9 +96,35 @@ export function shiftIsoDate(s: string, days: number): string {
   return d.toISOString().slice(0, 10)
 }
 
-/** Format a YYYY-MM-DD string for display: "Jun 1, 2026". */
+/**
+ * Format a YYYY-MM-DD string for display: "Jun 1, 2026".
+ * Always renders in UTC so the displayed date matches the ISO date
+ * stored in the DB regardless of the viewer's local timezone.
+ */
 export function formatIsoDate(s: string): string {
   const d = parseIsoDate(s)
   if (!d) return s
-  return d.toLocaleDateString(undefined, { month: 'short', day: 'numeric', year: 'numeric' })
+  return d.toLocaleDateString(undefined, {
+    month: 'short',
+    day: 'numeric',
+    year: 'numeric',
+    timeZone: 'UTC',
+  })
+}
+
+/**
+ * Format a Monday's ISO date as a Mon–Sun range label: "Jun 8 — Jun 14".
+ * Used by `WeekRangeNav` (Sprint 7) for the visible week range.
+ *
+ * Always renders in UTC so the date the user sees matches the ISO date
+ * stored in the DB regardless of the viewer's local timezone.
+ */
+export function formatWeekRange(mondayIso: string): string {
+  const monday = parseIsoDate(mondayIso)
+  if (!monday) return mondayIso
+  const sunday = new Date(monday)
+  sunday.setUTCDate(sunday.getUTCDate() + 6)
+  const fmt = (d: Date) =>
+    d.toLocaleDateString(undefined, { month: 'short', day: 'numeric', timeZone: 'UTC' })
+  return `${fmt(monday)} — ${fmt(sunday)}`
 }