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/surrealdb/test_lib.nim

@@ -0,0 +1,26 @@
+discard """
+  cmd: "nim c -d:reset $file"
+"""
+
+import std/json
+import std/unittest
+import ../../src/allographer/query_builder/libs/surreal/surreal_lib
+
+
+suite "SurrealDB lib helpers":
+  test "numToAlphabet":
+    check numToAlphabet(1) == "a"
+    check numToAlphabet(26) == "z"
+    check numToAlphabet(27) == "aa"
+
+  test "questionToDaller":
+    check questionToDaller("SELECT * FROM user WHERE name = ? AND age = ?") ==
+      "SELECT * FROM user WHERE name = $a AND age = $b"
+
+  test "dbFormat json args":
+    let sql = dbFormat(
+      "SELECT * FROM user WHERE name = ? AND age = ?",
+      %*["alice", 42]
+    )
+    check sql ==
+      "LET $a = \"alice\"; LET $b = 42; SELECT * FROM user WHERE name = $a AND age = $b"