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/clear_tables.nim

@@ -0,0 +1,71 @@
+import std/asyncdispatch
+import std/json
+import std/strformat
+import std/strutils
+import ../src/allographer/query_builder
+
+
+proc clearTables*(rdb:PostgresConnections) {.async.} =
+  try:
+    let tables = rdb.table("_allographer_migrations").orderBy("index", Desc) .get().await
+    for table in tables:
+      let tableName = table["name"].getStr()
+      if not tableName.startsWith("_"):
+        rdb.raw(&"DROP TABLE IF EXISTS \"{tableName}\"").exec().await
+
+    rdb.raw("DROP TABLE IF EXISTS \"_allographer_migrations\"").exec().await
+  except:
+    echo "error: ", getCurrentExceptionMsg()
+
+
+proc clearTables*(rdb:MariaDBConnections) {.async.} =
+  try:
+    let tables = rdb.table("_allographer_migrations").orderBy("index", Desc) .get().await
+    for table in tables:
+      let tableName = table["name"].getStr()
+      if not tableName.startsWith("_"):
+        rdb.raw(&"DROP TABLE IF EXISTS `{tableName}`").exec().await
+    
+    rdb.raw("DROP TABLE IF EXISTS `_allographer_migrations`").exec().await
+  except:
+    echo "error: ", getCurrentExceptionMsg()
+
+
+proc clearTables*(rdb:MySQLConnections) {.async.} =
+  try:
+    let tables = rdb.table("_allographer_migrations").orderBy("index", Desc) .get().await
+    for table in tables:
+      let tableName = table["name"].getStr()
+      if not tableName.startsWith("_"):
+        rdb.raw(&"DROP TABLE IF EXISTS `{tableName}`").exec().await
+    
+    rdb.raw("DROP TABLE IF EXISTS `_allographer_migrations`").exec().await
+  except:
+    echo "error: ", getCurrentExceptionMsg()
+
+
+proc clearTables*(rdb:SqliteConnections) {.async.} =
+  try:
+    let tables = rdb.table("_allographer_migrations").orderBy("index", Desc) .get().await
+    for table in tables:
+      let tableName = table["name"].getStr()
+      if not tableName.startsWith("_"):
+        rdb.raw(&"DROP TABLE IF EXISTS \"{tableName}\"").exec().await
+
+    rdb.raw("DROP TABLE IF EXISTS \"_allographer_migrations\"").exec().await
+  except:
+    echo "error: ", getCurrentExceptionMsg()
+
+
+proc clearTables*(rdb:SurrealConnections) {.async.} =
+  try:
+    let dbInfo = rdb.raw("INFO FOR DB").info().await
+    let tables = dbInfo[0]["result"]["tables"]
+    for (table, _) in tables.pairs:
+      if not table.startsWith("_"):
+        rdb.raw(&"REMOVE TABLE {table}").exec().await
+  
+    rdb.raw(&"REMOVE TABLE _allographer_migrations").exec().await
+    rdb.raw(&"REMOVE TABLE _autoincrement_sequences").exec().await
+  except:
+    echo "error: ", getCurrentExceptionMsg()