Update changelogs from fern repo (#2495)

Co-authored-by: dsinghvi <10870189+dsinghvi@users.noreply.github.com>

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2025-12-03.mdx

@@ -1,3 +1,15 @@
+## 3.0.0
+**`(break):`** **Breaking Change**: Enable `smart-casing` by default for all generators.
+
+Smart-casing improves naming conventions in generated SDKs by:
+- Capitalizing common initialisms like API, HTTP, ID, UUID, URL, HTML, JSON, XML, etc. in camelCase and PascalCase identifiers
+- Better handling of number-letter combinations (e.g., `v2` stays as `v2` instead of becoming `v_2`, `md5` stays as `md5` instead of `md_5`)
+
+**Migration Behavior**: The CLI will automatically upgrade your `generators.yml` to explicitly set `smart-casing: false` for all existing generators that don't have it configured. This preserves backwards compatibility for existing projects while enabling the improved naming for new projects.
+
+**Opting In**: To enable smart-casing for existing generators, remove the `smart-casing: false` line that the migration adds, or explicitly set `smart-casing: true`.
+
+
 ## 2.18.1
 **`(fix):`** Improve enum validation error messages to show which enum value has an invalid name. When the API source is OpenAPI, the error message now includes guidance about using the `x-fern-enum` extension to specify valid names.