content: align shrinkflation series frontmatter and nav links

Update frontmatter and footer navigation for dairy, frozen food,
household essentials, and snacks posts to match the cereal post series
format. Sets consistent series name "The Shrinkflation Files", correct
part numbers (2–5), and properly linked prev/next nav footers.

Refs: CAR-157, CAR-114

Co-authored-by: Frontend Frankie <frankie@cartsnitch.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

content/marketing/blog/shrinkflation-frozen-food-2026.md

@@ -1,13 +1,13 @@
 ---
-title: "Shrinkflation Report: Your Frozen Pizza Shrank and Your Ice Cream Did Too"
+title: "The Shrinkflation Files: Frozen Food"
 slug: shrinkflation-frozen-food-2026
-date: 2026-04-29
-author: CartSnitch Team
-category: Shrinkflation Report
-tags: [shrinkflation, frozen food, ice cream, frozen pizza, grocery prices]
 status: draft
-series: shrinkflation-case-studies
+version: 1.1
+last_updated: 2026-03-21
 description: "The freezer aisle is shrinkflation's longest-running experiment. Ice cream lost a quarter of its volume over 15 years. Frozen pizzas are lighter. And frozen dinners cost more per ounce than fresh ingredients."
+tags: ["shrinkflation", "frozen-food", "ice-cream", "grocery-prices", "data"]
+series: "The Shrinkflation Files"
+series_part: 3
 ---
 
 # Shrinkflation Report: Your Frozen Pizza Shrank and Your Ice Cream Did Too
@@ -103,4 +103,4 @@ That's the pattern playing out right now across frozen pizza, frozen meals, and
 
 ---
 
-*This is the fifth and final case study in our launch series of CartSnitch Shrinkflation Reports. Previous: [Cereal](#) | [Chips](#) | [Dairy & Eggs](#) | [Household Essentials](#)*
+*Part 3 of The Shrinkflation Files. [Part 2: Dairy and Eggs](/blog/shrinkflation-dairy-eggs-2026) | Up next: [Part 4: Household Essentials](/blog/shrinkflation-household-essentials-2026)*