fix(facade): pass previousContent to AgentExecutor for pipeline steps

The PipelineOrchestrator passes previousContent to preserve the agent
output history when running pipeline steps. This was being lost because
the facade's runAgentFn callback wasn't forwarding it to AgentExecutor.

Without this fix, pipeline steps would overwrite the agent-output.md
file instead of appending to it with a "Follow-up Session" separator.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/server/src/services/auto-mode/facade.ts

@@ -180,6 +180,7 @@ export class AutoModeServiceFacade {
             model: resolvedModel,
             planningMode: opts?.planningMode as PlanningMode | undefined,
             requirePlanApproval: opts?.requirePlanApproval as boolean | undefined,
+            previousContent: opts?.previousContent as string | undefined,
             systemPrompt: opts?.systemPrompt as string | undefined,
             autoLoadClaudeMd: opts?.autoLoadClaudeMd as boolean | undefined,
             thinkingLevel: opts?.thinkingLevel as ThinkingLevel | undefined,