feat: add overall timeout parameter to remote client (#2550)

## Summary
- Adds an overall `timeout` parameter to `TimeoutConfig` that limits the
total time for the entire request
- Can be set via config or `LANCE_CLIENT_TIMEOUT` environment variable
- Exposed in Python and Node.js bindings
- Includes comprehensive tests

## Test plan
- [x] Unit tests for Rust TimeoutConfig
- [x] Integration tests for Python bindings  
- [x] Integration tests for Node.js bindings
- [x] All existing tests pass

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

python/src/connection.rs

@@ -241,6 +241,7 @@ pub struct PyClientRetryConfig {
 
 #[derive(FromPyObject)]
 pub struct PyClientTimeoutConfig {
+    timeout: Option<Duration>,
     connect_timeout: Option<Duration>,
     read_timeout: Option<Duration>,
     pool_idle_timeout: Option<Duration>,
@@ -264,6 +265,7 @@ impl From<PyClientRetryConfig> for lancedb::remote::RetryConfig {
 impl From<PyClientTimeoutConfig> for lancedb::remote::TimeoutConfig {
     fn from(value: PyClientTimeoutConfig) -> Self {
         Self {
+            timeout: value.timeout,
             connect_timeout: value.connect_timeout,
             read_timeout: value.read_timeout,
             pool_idle_timeout: value.pool_idle_timeout,