feat(ui): close 6 P1 audit findings + 1 bonus mobile fix (Sprint 2)

- Dashboard MealCard: title truncate -> line-clamp-2, image shrinks to
  40x40 on <md to give the title room (B6).
- MealDetail: hero reworked to normal flow with stronger gradient;
  description runs through new cleanDescription() helper that strips
  14 spoonacular SEO patterns and trims to the last full sentence.
  Raw description moved to a 'Notes from source' disclosure (B7).
- Pantry: free-text aisle/unit replaced with <Select> populated from
  the new PANTRY_AISLES canonical enum; ingredient name field marked
  required. New PANTRY_AISLES export + PantryAisle type in types (B8).
- backend: alembic 0015_normalize_pantry_aisles maps free-text
  ingredient.aisle and grocery_item.aisle to canonical labels in a
  single transaction; downgrade raises (restore from snapshot).
  backend/scripts/dry_run_aisle_migration.sql is the read-only
  preview helper.
- ShoppingList: human-readable AISLE_LABEL map replaces raw snake_case
  aisle keys; 3-col stat grid with compact mobile sizing (B9 + S3.3).
- Pantry table: role/aria-label region and a right-edge white
  gradient hint at mobile horizontal overflow (B10).
- Recipes: pending/applied filter split, Apply and Reset buttons,
  active-count chip on the Filters button, role=region + aria-label
  on the panel (B11).
- Review/sprint2-verification.md and fix-ui-audit.md updated.

Build: npm run build (tsc + vite) green. tsc emits 0 errors.

Co-located audit + plan docs kept in sync: Review/ui-nielsen-audit.md
gains a Sprint 2 status block; fix-ui-audit.md has implementation
notes for each Sprint 2 task.

frontend/src/lib/utils.ts

@@ -0,0 +1,37 @@
+import { type ClassValue, clsx } from 'clsx';
+import { twMerge } from 'tailwind-merge';
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs));
+}
+
+const SEO_PATTERNS: RegExp[] = [
+  /\bFeatured In Group[^.!?]*[.!?]?/gi,
+  /\busers? who liked this recipe also liked[^.!?]*[.!?]?/gi,
+  /\bSimilar recipes (include|are)[^.!?]*[.!?]?/gi,
+  /\b\d+ people (found this recipe|made this recipe|have made this recipe)[^.!?]*[.!?]?/gi,
+  /\bOverall,? this recipe earns[^.!?]*[.!?]?/gi,
+  /\b\d+ people have made this recipe and would make it again\.?/gi,
+  /\b\d+ person has tried and liked this recipe\.?/gi,
+  /\bFor \$[\d.]+ per serving,? this recipe covers[^.!?]*[.!?]?/gi,
+  /\bThis recipe serves \d+\.?\s?/gi,
+  /\bIt is brought to you by [^.!?]+[.!?]?/gi,
+  /\bFrom preparation to the plate,? this recipe takes[^.!?]*[.!?]?/gi,
+  /\bIt works well as [^.!?]+[.!?]?/gi,
+  /\bIf you have [^,.]+(,\s*[^,.]+){0,5},? you can make it\.?/gi,
+  /\bOne serving contains [^.!?]+[.!?]?/gi,
+  /\bFor \d+ cents per serving,? this recipe covers[^.!?]*[.!?]?/gi,
+];
+
+export function cleanDescription(input: string | undefined | null, maxLen = 280): string {
+  if (!input) return '';
+  let s = input;
+  for (const re of SEO_PATTERNS) s = s.replace(re, '');
+  s = s.replace(/\s{2,}/g, ' ').replace(/\.\s*\./g, '.').trim();
+  if (s.length > maxLen) {
+    const cut = s.slice(0, maxLen);
+    const lastDot = cut.lastIndexOf('.');
+    s = (lastDot > 80 ? cut.slice(0, lastDot + 1) : cut.trimEnd() + '…');
+  }
+  return s;
+}