fix(clients): repair Python & Rust tests, add container test orchestration

- Python: fix wire protocol test method names (bool_val -> bool, etc.)
- Python: make integration tests and example fully async with pytest-asyncio
- Rust: add tokio dev-dependency and convert integration tests to async/await
- Rust: update ping_test example to async
- Nim: remove committed ELF build artifact
- Docker: add BARADB_HOST/BARADB_PORT env vars to test containers
- Docker: fix docker-compose.test.yml usage (remove --abort-on-container-exit)
- Add scripts/test-clients.sh for sequential client test runs
- Remove docker-compose.test.yml from .gitignore so it is tracked
- Fix repository URLs in Python and Rust READMEs

clients/nim/tests/test_integration.nim

@@ -1,15 +1,17 @@
 ## BaraDB Nim Client — Integration Tests
-## Requires a running BaraDB server on localhost:9472.
+## Requires a running BaraDB server.
+## Set BARADB_HOST / BARADB_PORT env vars to override defaults.
 
 import std/unittest
 import std/asyncdispatch
 import std/asyncnet
 import std/strutils
+import std/os
 import baradb/client
 
 const
-  TestHost = "127.0.0.1"
-  TestPort = 9472
+  TestHost = getEnv("BARADB_HOST", "127.0.0.1")
+  TestPort = parseInt(getEnv("BARADB_PORT", "9472"))
 
 proc serverAvailable(): bool =
   try: