fix(remote): make HTTP timeout errors actionable (#4650)

Remote `create_table` reader uploads can exceed the read deadline while
waiting for response headers, but reqwest's main error message only says
"error sending request". Make HTTP and retry errors explicitly identify
timeouts and name the relevant `client_config.timeout_config` settings
and environment variables, preserving typed sources, request metadata,
and retry classification.

Document that the read timeout covers waiting for headers during upload.
This implements the issue's diagnostic option: creation still uses one
streaming request, so large or slow readers may require a longer
`client_config.timeout_config.read_timeout`.

Validation:
- 48 focused Rust client, error, and retry tests passed. Regression
coverage holds an upload open until its read timeout and also exercises
TLS connection timeouts, with and without retries.
- 8 Python create-table and HTTP/retry error tests passed in the
uv-managed environment after rebuilding the extension, including reader
creation with read and overall timeouts.
- `cargo check --quiet --features remote --tests --examples` passed.
- `cargo clippy --quiet --features remote --tests --examples` passed.
- Rust formatting and Python package Ruff lint/format checks passed.
- Repository-wide `ruff check .` reports 49 existing findings under
`docs/web-tests`; those files are unchanged.

Fixes #4646

<!-- lance-gatekeeper-fix:v1 agent=ce1c040fa581f1748166ecb686d9c9c0
generation=1 -->

---------

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
Co-authored-by: Xuanwo <github@xuanwo.io>

nodejs/src/remote.rs

@@ -25,6 +25,10 @@ pub struct TimeoutConfig {
     /// The timeout for reading data from the server in seconds. Default is 300
     /// seconds (5 minutes). This can also be set via the environment variable
     /// `LANCE_CLIENT_READ_TIMEOUT`, as an integer number of seconds.
+    ///
+    /// This also applies while waiting for response headers during an upload.
+    /// A large or slowly produced request body (for example, when creating a
+    /// table) may need a longer timeout even if data is still being uploaded.
     pub read_timeout: Option<f64>,
     /// The timeout for keeping idle connections in the connection pool in seconds.
     /// Default is 300 seconds (5 minutes). This can also be set via the