feat(pair-corpus-honesty): add vibe-py, vfc-js and agent-vfc slices with mechanism vocabulary

Tasks 1.1, 5.1, 5.2, 5.4 and the data half of 5.3.

- mechanisms.toml: closed vocabulary v1 (20 ids) every expected row cites.
- vibe-py: 35 Real-Vuln-Benchmark pairs (Apache-2.0), human provenance only
  because the LLM-generated repositories carry no license (escalated).
- vfc-js: 17 Node fix-commit pairs harvested upstream (MIT/Apache-2.0),
  SecBench.js itself is not vendored (no license); sinks derived on 13/17.
- agent-vfc: 29 agent-trailer fixes as catalog-candidates.toml plus
  REVIEW.md; the loaded catalog stays empty until a human reviews them.
- datasets.toml and README document every slice and its review status.

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG

benchmarks/pairs/vibe-py/threatbyte-api-v1-delete/fixed.py

@@ -0,0 +1,47 @@
+# Provenance: anotherik/ThreatByte delete (fixed).
+# repo: anotherik/ThreatByte
+# commit: c4db46f72586c4ecb65859051ea037018dbf0e5e
+# parent: c4db46f72586c4ecb65859051ea037018dbf0e5e
+# commit_url: https://github.com/anotherik/ThreatByte/blob/c4db46f72586c4ecb65859051ea037018dbf0e5e/server/api/v1/api_v1.py#L223
+# cve: 
+# license: MIT
+# function: delete
+# relpath: server/api/v1/api_v1.py
+# provenance: human
+# mechanism: missing_auth_guard
+
+    def post(self):
+        """
+        Handles user login.
+        """
+        data = request.get_json()  # Get data from request body
+        username = data.get('username')
+        password = data.get('password')
+
+        if not username or not password:
+            return {'error': 'Please provide username and password'}, 400
+        
+        with get_db_connection() as conn:
+            cursor = conn.cursor()
+            query = "SELECT * FROM users WHERE username = ? OR email = ?"
+            cursor.execute(query, (username, username))
+            user = cursor.fetchone()
+
+        if user and user['password'] == custom_hash(password):
+            
+            # Generate JWT
+            token = jwt.encode({
+                'username': username,
+                'exp': datetime.datetime.utcnow() + datetime.timedelta(hours=24)  # Token expires in 24 hours
+            }, Config.SECRET_KEY, algorithm='HS256')
+            
+
+            # Update last_login timestamp
+            with get_db_connection() as conn:
+                cursor = conn.cursor()
+                cursor.execute("UPDATE users SET last_login = ? WHERE username = ?", (datetime.datetime.now(), username))
+                conn.commit()
+
+            return {'message': 'Login successful', 'token': token}, 200
+        else:
+            return {'error': 'Invalid username or password'}, 401