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-dairy-eggs-2026.md

@@ -1,13 +1,13 @@
 ---
-title: "Shrinkflation Report: The Incredible Cost of Eggs, Milk, and Yogurt in 2026"
+title: "The Shrinkflation Files: Dairy and Eggs"
 slug: shrinkflation-dairy-eggs-2026
-date: 2026-04-15
-author: CartSnitch Team
-category: Shrinkflation Report
-tags: [shrinkflation, dairy, eggs, milk, yogurt, grocery prices]
 status: draft
-series: shrinkflation-case-studies
+version: 1.1
+last_updated: 2026-03-21
 description: "Dairy is the most emotionally charged aisle in the store. Egg prices swing wildly, yogurt containers keep shrinking, and milk pricing defies logic. We tracked the numbers."
+tags: ["shrinkflation", "dairy", "eggs", "grocery-prices", "data"]
+series: "The Shrinkflation Files"
+series_part: 2
 ---
 
 # Shrinkflation Report: The Incredible Cost of Eggs, Milk, and Yogurt in 2026
@@ -95,4 +95,4 @@ The data is clear. The question is whether consumers have access to it. That's w
 
 ---
 
-*This is the third in a series of CartSnitch Shrinkflation Reports. Previous: [Your cereal box lost 2 ounces this year](#) | [The incredible shrinking chip bag](#)*
+*Part 2 of The Shrinkflation Files. [Part 1: Cereal](/blog/shrinkflation-cereal-2026) | Up next: [Part 3: Frozen Food](/blog/shrinkflation-frozen-food-2026)*