Fix CI Docker builds failing on public repo

The SSH agent setup step was conditional on the sponsors repo,
but the Docker builds unconditionally require SSH_AUTH_SOCK to be set.
Start the SSH agent on both repos - private keys are only loaded
when the CI_SSH_KEY_BOT secret is available.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: vinnybod

.github/workflows/lint-and-test.yml

@@ -102,8 +102,7 @@ jobs:
         with:
           submodules: 'recursive'
           token: ${{ secrets.RELEASE_TOKEN }}
-      - name: Set up SSH (sponsors only)
-        if: ${{ endswith(github.repository, 'Empire-Sponsors') }}
+      - name: Set up SSH
         run: |
           eval "$(ssh-agent -s)"
           echo "SSH_AUTH_SOCK=$SSH_AUTH_SOCK" >> $GITHUB_ENV
@@ -143,8 +142,7 @@ jobs:
         with:
           submodules: 'recursive'
           depth: 0
-      - name: Set up SSH (sponsors only)
-        if: ${{ endswith(github.repository, 'Empire-Sponsors') }}
+      - name: Set up SSH
         run: |
           eval "$(ssh-agent -s)"
           echo "SSH_AUTH_SOCK=$SSH_AUTH_SOCK" >> $GITHUB_ENV