feat(clients): add nim-allographer client with BaraDB driver support

- Pure Nim wire protocol client (async + sync, no C FFI)
- Query Builder: fluent API, SQL generator, execution, transactions
- Schema Builder: create/alter/drop tables, column operations
- Connection pool with aging and timeout handling
- ORM integration via compile-time DB_BARADB switch
- Tests: test_open, test_query
- Documentation: README.md, PLAN_BARADB.md

clients/nim-allographer/example/.env

@@ -0,0 +1,22 @@
+DB_SQLITE=true
+DB_POSTGRES=true
+DB_MARIADB=true
+DB_SURREAL=true
+
+SQLITE_HOST="/root/project/example/db.sqlite3"
+# SQLITE_HOST=":memory:"
+MY_HOST=mysql
+MARIA_HOST=mariadb
+MY_PORT=3306
+PG_HOST=postgres
+PG_PORT=5432
+DB_USER=user
+DB_PASSWORD=pass
+DB_DATABASE=database
+DB_MAX_CONNECTION=95
+DB_TIMEOUT=30
+
+# Logging
+LOG_IS_DISPLAY=true
+LOG_IS_FILE=false
+LOG_DIR="/root/project/example/logs"