## Problem
The `front-sb-test` jobs were sometimes failing with:
```
Error: EEXIST: file already exists, mkdir './storybook-static/images/icons/android'
```
## Root Cause
1. `front-sb-build` builds storybook and saves NX cache (but NOT
`storybook-static/` folder)
2. `front-sb-test` restores NX cache - NX thinks build is done, but
`storybook-static/` doesn't exist
3. `storybook:serve:static` depends on `storybook:build`, so NX re-runs
the build
4. Race condition in Storybook's file copy causes EEXIST error
The `storybook-static` folder was **never** included in the cache paths
- I verified this by checking git history back to when the save-cache
action was created.
## Solution
Add `storybook-static` to the `additional-paths` for both save and
restore cache steps. This ensures the built storybook is properly cached
and restored, eliminating the need for a rebuild during tests.
