docs: contribution optimizations (#5154)

* docs: contribution optimizations

Added instructions for setting up credentials and handling .env file issues.

* Update Husky installation instructions

Added instructions to run 'npm run prepare' for Husky validation.

* auto update snapshots (#5155)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* auto update snapshots (#5171)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: mfranzke

CONTRIBUTING.md

@@ -17,6 +17,8 @@ node node_modules/@db-ux/db-theme-icons/build/scripts/index.js
 node node_modules/@db-ux/db-theme-illustrative-icons/build/scripts/index.js
 ```
 
+If you're contributing from a fork in your user space, please also set up those credentials from the Marketing portal in your fork repository as repository secrets. You need these credentials for the pipeline to decrypt the brand assets correctly.
+
 > [!NOTE]
 > If you missed setting up the `.env`-file before running `npm install`, you may need to re-install your packages to ensure the postinstall scrips are executed for decrypting the fonts and other artifacts (`rm --recursive --force node_modules/@db-ux/db-theme* && npm update @db-ux/db-theme`)
 
@@ -29,7 +31,7 @@ npm run dev
 
 ## Make changes / Before you commit
 
-Please ensure that **Husky** is installed correctly to validate your changes.
+Please ensure that **Husky** is installed correctly to validate your changes, e.g. by running `npm run prepare` in the codebase.
 
 Please verify you are using a valid branch name as described by the pattern in your [`package.json`](./package.json) in the section `validate-branch-name`.