[client-v2, jdbc-v2] Make execution TIMEOUT error optionally retriable

## Description

Current `159, TIMEOUT_EXCEEDED` is retried unconditionally. It should be a dedicated failure cause selectable per operation because different queries need different behavior:

| Query Type | Scenario | Retriable? | Recommended Action |
| :--- | :--- | :---: | :--- |
| **`SELECT`** | Pure read operations | **Yes** | Retry with exponential backoff or redirect to a replica node. |
| **`SELECT`** | Heavy unoptimized query hitting `max_execution_time` | **No** | Do not retry under identical settings. Increase `max_execution_time` or rewrite query. |
| **`INSERT`** | MergeTree tables with deduplication active (`insert_deduplicate = 1`) | **Yes** | Safe to retry using the exact same data block structure. |
| **`INSERT`** | Tables without block deduplication | **No** | **Unsafe.** Partial blocks may have been written; retrying risks duplicate rows. Check table state first. |
| **`DDL / Mutations`** | `ALTER`, `OPTIMIZE`, or background mutations | **No** | Inspect system tables (`system.mutations`, `system.merges`) before re-executing. |

Start by tracing TIMEOUT_EXCEEDED handling in client-v2 and jdbc-v2, especially how the 159 failure is currently retried. Compare operation handling for SELECT, INSERT, and DDL or mutations, then determine where per-operation retry selection belongs. Done means timeout retry behavior can differ by operation and reflects the safety distinctions described in the table.

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