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/tests/sqlite/connections.nim

@@ -0,0 +1,11 @@
+import std/os
+import std/strutils
+import ../../src/allographer/connection
+
+let
+  sqliteHost = getEnv("SQLITE_HOST")
+  maxConnections = getEnv("DB_MAX_CONNECTION").parseInt
+  timeout = getEnv("DB_TIMEOUT").parseInt
+
+echo "sqliteHost: ", sqliteHost
+let sqlite* = dbOpen(SQLite3, sqliteHost, maxConnections, timeout, shouldDisplayLog=true)