fix: grant schema privileges to database user for PostgreSQL 15+

PostgreSQL 15+ changed the default security model where the PUBLIC role
no longer has CREATE privilege on the public schema. This caused Flyway
migrations to fail during integration tests with "permission denied for
schema public" errors.

Added explicit GRANT commands to:
- Grant all privileges on the public schema to the database user
- Grant privileges on all existing tables in the schema
- Set default privileges for future tables created in the schema

This fix ensures the yaci-indexer can successfully run database migrations
during Docker container initialization.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: matiwinnetou

docker/dockerfiles/postgres/entrypoint.sh

@@ -125,6 +125,12 @@ create_database_and_user() {
         sudo -u postgres "$PG_BIN/psql" -U postgres -p "$DB_PORT" -c "GRANT ALL PRIVILEGES ON DATABASE \"$DB_NAME\" to \"$DB_USER\";" > /dev/null
     fi
 
+    # Grant schema privileges (required for PostgreSQL 15+)
+    echo "Granting schema privileges..."
+    sudo -u postgres "$PG_BIN/psql" -U postgres -p "$DB_PORT" -d "$DB_NAME" -c "GRANT ALL ON SCHEMA public TO \"$DB_USER\";" > /dev/null
+    sudo -u postgres "$PG_BIN/psql" -U postgres -p "$DB_PORT" -d "$DB_NAME" -c "GRANT ALL ON ALL TABLES IN SCHEMA public TO \"$DB_USER\";" > /dev/null
+    sudo -u postgres "$PG_BIN/psql" -U postgres -p "$DB_PORT" -d "$DB_NAME" -c "ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO \"$DB_USER\";" > /dev/null
+
     echo "User configured"
 }