chore: add changeset

.changeset/eleven-keys-decide.md

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+---
+"effect": major
+---
+
+## Major: Swap type parameters for `Left` and `Right` to align with `Either`
+
+**WHAT the breaking change is:**
+
+- The type parameters for `Left<L, R>` and `Right<L, R>` have been swapped to `Left<R, L>` and `Right<R, L>`, respectively. This brings them in line with the parameter ordering of `Either<R, L>`.
+
+**WHY the change was made:**
+
+- This change ensures consistency across the codebase. In `Either<R, L>`, `R` is used for the "right" value and `L` for the "left" value. Aligning `Left` and `Right` with `Either` reduces confusion.
+
+**HOW a consumer should update their code:**
+
+- Any usage of `Left<L, R>` should be replaced with `Left<R, L>`.
+- Any usage of `Right<L, R>` should be replaced with `Right<R, L>`.
+- For example:
+  - `Left<string, number>` should now be `Left<number, string>`.
+  - `Right<string, number>` should now be `Right<number, string>`.