chore: Standardize Oracle tunnel port to 1521

Changed SSH tunnel local port from 1526 to 1521 to match Oracle's
default port, simplifying configuration across environments.

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

setup_production.sh

@@ -85,7 +85,7 @@ NODE_ENV=production
 ORACLE_USER=CONTAFIN_ORACLE
 ORACLE_PASSWORD=${ORACLE_PASSWORD}
 ORACLE_HOST=localhost  # Through SSH tunnel
-ORACLE_PORT=1526
+ORACLE_PORT=1521
 ORACLE_SID=ROA
 
 # User Authentication Credentials