Fix: use sed to replace Neo4j conf keys, no duplicate declarations

Dockerfile

@@ -49,21 +49,22 @@ RUN curl -fsSL https://debian.neo4j.com/neotechnology.gpg.key \
 ENV NEO4J_HOME=/var/lib/neo4j
 ENV PATH="/usr/bin:${PATH}"
 
-# ── Neo4j configuration ────────────────────────────────────────────────────────
-RUN { \
-    echo "server.bolt.listen_address=0.0.0.0:7687"; \
-    echo "server.http.listen_address=0.0.0.0:7474"; \
-    echo "server.memory.heap.initial_size=512m"; \
-    echo "server.memory.heap.max_size=1g"; \
-    echo "server.memory.pagecache.size=256m"; \
-    echo "db.transaction.timeout=60s"; \
-    echo "dbms.logs.query.enabled=OFF"; \
-    echo "dbms.security.procedures.unrestricted=apoc.*"; \
-    echo "dbms.security.procedures.allowlist=apoc.*"; \
-    echo "server.directories.data=/data/neo4j/data"; \
-    echo "server.directories.logs=/data/neo4j/logs"; \
-    echo "server.directories.run=/data/neo4j/run"; \
-} >> /etc/neo4j/neo4j.conf
+# ── Neo4j configuration (sed replaces existing keys, avoids duplicate errors) ──
+RUN CFG=/etc/neo4j/neo4j.conf && \
+    sed -i 's|^#*\s*server\.bolt\.listen_address=.*|server.bolt.listen_address=0.0.0.0:7687|' $CFG && \
+    sed -i 's|^#*\s*server\.http\.listen_address=.*|server.http.listen_address=0.0.0.0:7474|' $CFG && \
+    sed -i 's|^#*\s*server\.directories\.data=.*|server.directories.data=/data/neo4j/data|' $CFG && \
+    sed -i 's|^#*\s*server\.directories\.logs=.*|server.directories.logs=/data/neo4j/logs|' $CFG && \
+    sed -i 's|^#*\s*server\.directories\.run=.*|server.directories.run=/data/neo4j/run|' $CFG && \
+    sed -i 's|^#*\s*server\.memory\.heap\.initial_size=.*|server.memory.heap.initial_size=512m|' $CFG && \
+    sed -i 's|^#*\s*server\.memory\.heap\.max_size=.*|server.memory.heap.max_size=1g|' $CFG && \
+    sed -i 's|^#*\s*server\.memory\.pagecache\.size=.*|server.memory.pagecache.size=256m|' $CFG && \
+    { \
+      echo "db.transaction.timeout=60s"; \
+      echo "dbms.logs.query.enabled=OFF"; \
+      echo "dbms.security.procedures.unrestricted=apoc.*"; \
+      echo "dbms.security.procedures.allowlist=apoc.*"; \
+    } >> $CFG
 
 # ── Python backend ────────────────────────────────────────────────────────────
 WORKDIR /app/backend