fix: use ssh-keyscan to populate known_hosts for Dagger

scripts/setup_dagger_remote.sh

@@ -22,23 +22,23 @@ chmod 700 ~/.ssh
 echo "$DAGGER_SSH_KEY" > ~/.ssh/dagger_key
 chmod 600 ~/.ssh/dagger_key
 
+# Add remote host to known_hosts to satisfy Dagger's internal SSH client
+ssh-keyscan -H "$DAGGER_ENGINE_HOST" >> ~/.ssh/known_hosts 2>/dev/null
+
 # Use ssh-agent to manage the key for Dagger's internal SSH client
 eval "$(ssh-agent -s)"
 ssh-add ~/.ssh/dagger_key
 
 # Export _EXPERIMENTAL_DAGGER_RUNNER_HOST for redirection
-# Dagger's Go SSH client will now use the agent to find the key
 export _EXPERIMENTAL_DAGGER_RUNNER_HOST="ssh://dagger@$DAGGER_ENGINE_HOST"
 if [ -n "${GITHUB_ENV:-}" ]; then
     echo "_EXPERIMENTAL_DAGGER_RUNNER_HOST=ssh://dagger@$DAGGER_ENGINE_HOST" >> "$GITHUB_ENV"
-    # Also pass the agent socket if needed, though Dagger usually handles this if exported
     echo "SSH_AUTH_SOCK=$SSH_AUTH_SOCK" >> "$GITHUB_ENV"
     echo "SSH_AGENT_PID=$SSH_AGENT_PID" >> "$GITHUB_ENV"
 fi
 
 # Verify
 echo "Verifying connection to remote Dagger engine..."
-# Ensure remote dagger knows which socket to use
 if ! timeout 45 dagger query --progress=plain '{ version }' ; then
     echo "Error: Dagger engine unreachable via SSH at $DAGGER_ENGINE_HOST"
     # Debug: try to just run id over ssh