feat(sql): bind query parameters over Flight DoExchange (#4345)

`execute_query` / `execute_query_async` can now bind values to `$1` /
`$name` placeholders instead of splicing them into the SQL text. The
values travel as Arrow, so a float32 keeps its exact bits and type and a
vector stays a compact `FixedSizeList` (3 KB for 768 dims rather than ~9
KB of decimal literals parsed back as Float64).

```rust
db.execute_query_async("SELECT id FROM docs ORDER BY distance(vector, $vector) LIMIT $k")
    .parameters(batch) // one-row RecordBatch
    .execute()
    .await?;
```

```python
db.execute_query(sql, parameters={"vector": np.float32_vector, "k": 10})
```

- A statement with parameters is sent on one `DoExchange`: the first
message carries the `CommandStatementQuery` descriptor and the parameter
schema, the second the one-row batch, and the result rows stream back on
the same call. Statements without parameters keep `PollFlightInfo` +
`DoGet` unchanged.
- Column `i` binds `$<i+1>`; a column whose name is not a number also
binds `$<name>`. Python accepts a list (positional), a dict (named), or
a one-row `RecordBatch` / `Table`; 1-D numpy / pyarrow arrays become a
`FixedSizeList` of their element type.
- A parameterized query runs on its call: `cancel()`, dropping the
handle before reading, or dropping the reader ends the call and stops
the server-side statement. It is still registered for `describe_query`.
- `Database::execute_query_async` now takes an `ExecuteQueryRequest`
options struct.

Server side: lancedb/sophon#8256.

docs/src/python/python.md

@@ -86,6 +86,15 @@ print(query.describe().status)
 for batch in query.reader():
     print(batch.num_rows)
 
+# Values bind to $1 / $name placeholders and travel as Arrow, so a float32
+# stays a float32 and a vector stays a compact fixed-size list:
+import numpy as np
+
+reader = db.execute_query(
+    "SELECT id FROM docs ORDER BY distance(vector, $vector) LIMIT $k",
+    parameters={"vector": np.random.rand(768).astype(np.float32), "k": 10},
+)
+
 # The async connection exposes the same lifecycle without blocking:
 # async_db = await lancedb.connect_async(
 #     "db://analytics",
@@ -201,6 +210,8 @@ listing a storage directory.
 
 ::: lancedb.sql.QueryDescription
 
+::: lancedb.sql.QueryParameters
+
 ## Materialized Views (Synchronous)
 
 ::: lancedb.materialized_view.MaterializedView