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-household-essentials-2026.md

@@ -1,13 +1,13 @@
 ---
-title: "Shrinkflation Report: Fewer Sheets, Same Price — The Household Essentials Squeeze"
+title: "The Shrinkflation Files: Household Essentials"
 slug: shrinkflation-household-essentials-2026
-date: 2026-04-22
-author: CartSnitch Team
-category: Shrinkflation Report
-tags: [shrinkflation, household, paper towels, detergent, toilet paper, grocery prices]
 status: draft
-series: shrinkflation-case-studies
+version: 1.1
+last_updated: 2026-03-21
 description: "Toilet paper has fewer sheets. Detergent does fewer loads. Paper towels are thinner. We tracked the household essentials aisle and the numbers are stark."
+tags: ["shrinkflation", "household", "paper-towels", "detergent", "grocery-prices", "data"]
+series: "The Shrinkflation Files"
+series_part: 4
 ---
 
 # Shrinkflation Report: Fewer Sheets, Same Price — The Household Essentials Squeeze
@@ -99,4 +99,4 @@ But the data doesn't lie. And now you have it.
 
 ---
 
-*This is the fourth in a series of CartSnitch Shrinkflation Reports. Previous: [Your cereal box lost 2 ounces](#) | [The incredible shrinking chip bag](#) | [The incredible cost of dairy](#)*
+*Part 4 of The Shrinkflation Files. [Part 3: Frozen Food](/blog/shrinkflation-frozen-food-2026) | Up next: [Part 5: Snacks and Chips](/blog/shrinkflation-snacks-chips-2026)*