feat(clients): professional clients with tests, CI/CD, and examples

- Python: pyproject.toml, pytest suite (unit + integration), README, examples
- JavaScript: package.json, TypeScript definitions, node:test suite, README, examples
- Nim: integration tests, examples, README, improved nimble tasks
- Rust: fixed nodelay/localhost IPv6 bug, integration tests, examples, README
- Added GitHub Actions CI for all 4 clients against Docker server
- Added docker-compose.test.yml for local integration testing
- Added .gitignore for each client

clients/nim/tests/test_integration.nim

@@ -0,0 +1,119 @@
+## BaraDB Nim Client — Integration Tests
+## Requires a running BaraDB server on localhost:9472.
+
+import std/unittest
+import std/asyncdispatch
+import std/asyncnet
+import std/strutils
+import baradb/client
+
+const
+  TestHost = "127.0.0.1"
+  TestPort = 9472
+
+proc serverAvailable(): bool =
+  try:
+    var socket = newAsyncSocket()
+    waitFor socket.connect(TestHost, Port(TestPort))
+    socket.close()
+    return true
+  except:
+    return false
+
+let hasServer = serverAvailable()
+
+suite "Integration: Connection":
+  test "Connect and close":
+    if not hasServer:
+      skip()
+    var client = newClient(ClientConfig(host: TestHost, port: TestPort))
+    check not client.isConnected
+    waitFor client.connect()
+    check client.isConnected
+    client.close()
+    check not client.isConnected
+
+  test "Ping":
+    if not hasServer:
+      skip()
+    var client = newClient(ClientConfig(host: TestHost, port: TestPort))
+    waitFor client.connect()
+    check (waitFor client.ping()) == true
+    client.close()
+
+suite "Integration: Query":
+  test "Simple SELECT":
+    if not hasServer:
+      skip()
+    var client = newClient(ClientConfig(host: TestHost, port: TestPort))
+    waitFor client.connect()
+    let result = waitFor client.query("SELECT 1 as one")
+    check result.rowCount >= 0
+    client.close()
+
+  test "Parameterized query":
+    if not hasServer:
+      skip()
+    var client = newClient(ClientConfig(host: TestHost, port: TestPort))
+    waitFor client.connect()
+    let result = waitFor client.query(
+      "SELECT $1 as num, $2 as txt",
+      @[WireValue(kind: fkInt64, int64Val: 42), WireValue(kind: fkString, strVal: "hello")]
+    )
+    check result.rowCount >= 0
+    client.close()
+
+suite "Integration: DDL & DML":
+  test "Create table, insert, select, drop":
+    if not hasServer:
+      skip()
+    var client = newClient(ClientConfig(host: TestHost, port: TestPort))
+    waitFor client.connect()
+
+    try:
+      discard waitFor client.exec("DROP TABLE IF EXISTS nim_test_users")
+    except:
+      discard
+
+    discard waitFor client.exec("CREATE TABLE nim_test_users (id INT PRIMARY KEY, name STRING, age INT)")
+    let affected = waitFor client.exec("INSERT INTO nim_test_users (id, name, age) VALUES (1, 'Alice', 30)")
+    check affected >= 0
+
+    let result = waitFor client.query("SELECT name, age FROM nim_test_users WHERE id = 1")
+    check result.rowCount == 1
+    client.close()
+
+suite "Integration: QueryBuilder":
+  test "Builder exec":
+    if not hasServer:
+      skip()
+    var client = newClient(ClientConfig(host: TestHost, port: TestPort))
+    waitFor client.connect()
+
+    try:
+      discard waitFor client.exec("DROP TABLE IF EXISTS nim_test_products")
+    except:
+      discard
+
+    discard waitFor client.exec("CREATE TABLE nim_test_products (id INT PRIMARY KEY, name STRING, price FLOAT)")
+    discard waitFor client.exec("INSERT INTO nim_test_products (id, name, price) VALUES (1, 'Widget', 9.99)")
+
+    let result = waitFor newQueryBuilder(client)
+      .select("name", "price")
+      .from("nim_test_products")
+      .where("id = 1")
+      .exec()
+    check result.rowCount == 1
+
+    discard waitFor client.exec("DROP TABLE nim_test_products")
+    client.close()
+
+suite "Integration: SyncClient":
+  test "Sync query":
+    if not hasServer:
+      skip()
+    var client = newSyncClient(ClientConfig(host: TestHost, port: TestPort))
+    client.connect()
+    let result = client.query("SELECT 1 as one")
+    check result.rowCount >= 0
+    client.close()