docs: fix contributor docs links and typos (#18637)

## Summary

This PR fixes several small documentation issues in the contributor and
setup guides:

- fixes broken docs links in the root README
- corrects multiple typos and capitalization issues in contributor docs
- fixes malformed Markdown for the Redis command in local setup
- improves wording in the Docker Compose self-hosting guide

## Changes

- updated README installation links to the current docs routes
- changed `Open-source` to `open-source`
- fixed `specially` -> `especially` in the frontend style guide
- normalized `MacOS` -> `macOS`, `powershell` -> `PowerShell`, and
`Postgresql` -> `PostgreSQL`
- replaced the invalid `localhost:5432` Markdown link with inline code
- fixed the malformed fenced code block for `brew services start redis`
- cleaned up Redis naming/capitalization and a few grammar issues in the
setup docs
- improved the warning and environment-variable wording in the Docker
Compose guide

## Testing

- not run; docs-only changes

---------

Co-authored-by: Charles Bochet <[email protected]>

.github/workflows/docs-i18n-pull.yaml

@@ -40,7 +40,8 @@ jobs:
         uses: actions/checkout@v4
         with:
           token: ${{ github.token }}
-          ref: ${{ github.event_name == 'pull_request' && github.head_ref || github.ref }}
+          repository: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name || github.repository }}
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.ref }}
 
       - name: Install dependencies
         uses: ./.github/actions/yarn-install
@@ -111,7 +112,7 @@ jobs:
         run: yarn docs:generate-paths
 
       - name: Commit artifacts to pull request branch
-        if: github.event_name == 'pull_request'
+        if: github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository
         run: |
           git add packages/twenty-docs/docs.json packages/twenty-docs/navigation/navigation.template.json packages/twenty-shared/src/constants/DocumentationPaths.ts
           if git diff --staged --quiet --exit-code; then
@@ -149,4 +150,3 @@ jobs:
           fi
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-