fix: use PAT token for index rebuild and add study_014 to index

The sync workflow was failing because the default GITHUB_TOKEN cannot
push to the protected main branch. Switch to PAT_TOKEN secret. Also
rebuild studies_index.json to include study_014.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: assassin808

.github/workflows/sync-studies-index.yml

@@ -13,6 +13,8 @@ jobs:
       contents: write
     steps:
       - uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.PAT_TOKEN }}
       - uses: actions/setup-python@v5
         with:
           python-version: "3.11"

co_website/data/studies_index.json

@@ -149,6 +149,23 @@
           "github": "https://github.com/zgk2003"
         }
       ]
+    },
+    {
+      "study_id": "study_014",
+      "title": "Do Auctioneers Pick Optimal Reserve Prices?",
+      "authors": [
+        "Andrew M. Davis",
+        "Elena Katok",
+        "Anthony M. Kwasnica"
+      ],
+      "year": 2011,
+      "description": "This study investigates how auctioneers set reserve prices in second-price sealed-bid auctions. A well-established theoretical result, assuming risk neutrality of the seller, is that the optimal reserve price should not depend on the number of participating bidders. In a set of controlled laboratory experiments, it is found that seller behavior often deviates from the theoretical benchmarks: sellers systematically increase their reserve prices as the number of bidders grows, contrary to standard auction theory.",
+      "contributors": [
+        {
+          "name": "Yuanjun Feng",
+          "github": "https://github.com/diana3135"
+        }
+      ]
     }
   ]
 }