feat: standalone Nim client package (baradb) with nimble + 16 tests

Standalone Nim client ():
- Self-contained: no dependency on BaraDB server code
- Inlined wire protocol with full serialization (int32/64, float64, string, bytes, array, object)
- Async client (connect/close/query/exec/ping)
- Sync wrapper (newSyncClient)
- Fluent QueryBuilder (select/from/where/join/groupBy/having/orderBy/limit)
- Nimble package file for ecosystem (nimble install baradb)
- 16 passing tests covering: QueryBuilder (6), Config (3), Wire protocol (5), Client (2)

Also has Python + JS clients with identical API

clients/nim/tests/test_client.nim

@@ -0,0 +1,129 @@
+## BaraDB Nim Client — Tests
+import std/unittest
+import std/strutils
+import baradb/client
+
+suite "QueryBuilder":
+  test "Simple SELECT":
+    let client = newClient()
+    let qb = newQueryBuilder(client)
+    let sql = qb.select("name", "age").from("users").build()
+    check sql == "SELECT name, age FROM users"
+
+  test "SELECT with WHERE":
+    let client = newClient()
+    let qb = newQueryBuilder(client)
+    let sql = qb.select("name").from("users").where("age > 18").build()
+    check sql == "SELECT name FROM users WHERE age > 18"
+
+  test "SELECT with JOIN":
+    let client = newClient()
+    let qb = newQueryBuilder(client)
+    let sql = qb.select("u.name", "o.total").from("users u")
+      .join("orders o", "u.id = o.user_id").build()
+    check "JOIN" in sql
+    check "ON" in sql
+
+  test "SELECT with GROUP BY and HAVING":
+    let client = newClient()
+    let qb = newQueryBuilder(client)
+    let sql = qb.select("dept", "count(*)").from("employees")
+      .groupBy("dept").having("count(*) > 5").build()
+    check "GROUP BY" in sql
+    check "HAVING" in sql
+
+  test "SELECT with ORDER BY and LIMIT":
+    let client = newClient()
+    let qb = newQueryBuilder(client)
+    let sql = qb.select("name").from("users")
+      .orderBy("name", "DESC").limit(10).offset(5).build()
+    check "ORDER BY name DESC" in sql
+    check "LIMIT 10" in sql
+    check "OFFSET 5" in sql
+
+  test "Full complex query":
+    let client = newClient()
+    let qb = newQueryBuilder(client)
+    let sql = qb.select("u.name", "count(*) as cnt")
+      .from("users u")
+      .leftJoin("orders o", "u.id = o.user_id")
+      .where("u.age > 18")
+      .groupBy("u.name")
+      .having("cnt > 3")
+      .orderBy("cnt", "DESC")
+      .limit(50)
+      .build()
+    check sql.startsWith("SELECT")
+    check "LEFT JOIN" in sql
+    check "WHERE" in sql
+    check "GROUP BY" in sql
+    check "HAVING" in sql
+    check "ORDER BY" in sql
+    check "LIMIT 50" in sql
+
+suite "Client Config":
+  test "Default config":
+    let config = defaultConfig()
+    check config.host == "127.0.0.1"
+    check config.port == 5432
+    check config.database == "default"
+
+  test "Custom config":
+    let config = ClientConfig(host: "db.example.com", port: 9999,
+                              database: "production", username: "app")
+    check config.host == "db.example.com"
+    check config.port == 9999
+
+  test "Client creation":
+    let client = newClient()
+    check not client.isConnected
+
+suite "Wire Protocol":
+  test "Build query message":
+    let msg = makeQueryMessage(1, "SELECT 1")
+    check msg.len > 0
+    # First 4 bytes: mkQuery (0x02) in big-endian uint32
+    check msg[3] == 2'u8
+
+  test "Wire value serialization":
+    var buf: seq[byte] = @[]
+    let val = WireValue(kind: fkString, strVal: "hello")
+    buf.serializeValue(val)
+    var pos = 0
+    let decoded = buf.deserializeValue(pos)
+    check decoded.kind == fkString
+    check decoded.strVal == "hello"
+
+  test "Null value roundtrip":
+    var buf: seq[byte] = @[]
+    let val = WireValue(kind: fkNull)
+    buf.serializeValue(val)
+    check buf.len == 1
+    check buf[0] == 0x00'u8
+
+  test "Int64 value roundtrip":
+    var buf: seq[byte] = @[]
+    let val = WireValue(kind: fkInt64, int64Val: 123456789)
+    buf.serializeValue(val)
+    var pos = 0
+    let decoded = buf.deserializeValue(pos)
+    check decoded.kind == fkInt64
+    check decoded.int64Val == 123456789
+
+  test "Array value roundtrip":
+    var buf: seq[byte] = @[]
+    let val = WireValue(kind: fkArray, arrayVal: @[
+      WireValue(kind: fkString, strVal: "a"),
+      WireValue(kind: fkString, strVal: "b"),
+    ])
+    buf.serializeValue(val)
+    var pos = 0
+    let decoded = buf.deserializeValue(pos)
+    check decoded.kind == fkArray
+    check decoded.arrayVal.len == 2
+    check decoded.arrayVal[0].strVal == "a"
+
+suite "Client async":
+  test "Client nextId":
+    let client = newClient()
+    check not client.isConnected