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/src/allographer/env.nim

@@ -0,0 +1,27 @@
+import std/os
+import std/strutils
+import std/streams
+import std/parsecfg
+
+for f in walkDir(getCurrentDir()):
+  if f.path.split("/")[^1] == ".env":
+    let path = getCurrentDir() / ".env"
+    var f = newFileStream(path, fmRead)
+    var p: CfgParser
+    open(p, f, path)
+    while true:
+      let e = next(p)
+      case e.kind
+      of cfgEof: break
+      of cfgKeyValuePair: putEnv(e.key, e.value)
+      else: discard
+    break
+
+
+const
+  isExistsSqlite* = getEnv("DB_SQLITE", $false).parseBool
+  isExistsPostgres* = getEnv("DB_POSTGRES", $false).parseBool
+  isExistsMysql* = getEnv("DB_MYSQL", $false).parseBool
+  isExistsMariadb* = getEnv("DB_MARIADB", $false).parseBool
+  isExistsSurrealdb* = getEnv("DB_SURREAL", $false).parseBool
+  isExistsBaradb* = getEnv("DB_BARADB", $false).parseBool