Chore: Clean up workflow files and artifacts

- Update .gitignore to explicitly ignore data directory contents
- Remove unused workflow file
- Remove test artifact file
- Remove unused ai_backlinker README

.gitignore

@@ -16,6 +16,7 @@ artifacts
 .opencode
 
 data/
+data/*
 
 .trae/
 /backend/database/migrations/*

artifacts/podcast_billing_sequence_report.json

@@ -1,43 +0,0 @@
-{
-  "preflight": {
-    "success": true,
-    "can_proceed": true,
-    "estimated_cost": 0.3
-  },
-  "operations": {
-    "analysis_title_suggestions": [
-      "AI Agents in 2026",
-      "Ship Faster with AI",
-      "Startup AI Playbook"
-    ],
-    "research_provider": "exa",
-    "research_cost": 0.015,
-    "video_task_status": "completed"
-  },
-  "dashboard_deltas": {
-    "total_calls_before": 1,
-    "total_calls_after": 5,
-    "delta_calls": 4,
-    "total_cost_before": 0.09,
-    "total_cost_after": 0.488,
-    "delta_cost": 0.398,
-    "projected_monthly_cost_before": 0.09,
-    "projected_monthly_cost_after": 0.49,
-    "delta_projected_monthly_cost": 0.4
-  },
-  "provider_cost_deltas": {
-    "exa": 0.005,
-    "huggingface": 0.003,
-    "wavespeed": 0.39
-  },
-  "acceptance": {
-    "passed": true,
-    "criteria": {
-      "preflight_success": true,
-      "usage_cost_incremented": true,
-      "usage_call_incremented": true,
-      "projection_incremented": true,
-      "provider_delta_present": true
-    }
-  }
-}