docs: document LIGHTDASH_QUERY_RETRY_ON_TRANSIENT_ERRORS env var (#746)

Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>

Author: mintlify[bot]

self-host/customize-deployment/environment-variables.mdx

@@ -30,6 +30,7 @@ This is a reference to all environment variables that can be used to configure a
 | `LIGHTDASH_QUERY_MAX_LIMIT`                  | Query max rows limit (default=5000)                                                                                                                                                                                                                                                                                         |
 | `LIGHTDASH_QUERY_DEFAULT_LIMIT`              | Default number of rows to return in a query (default=500)                                                                                                                                                                                                                                                                   |
 | `LIGHTDASH_QUERY_MAX_PAGE_SIZE`              | Maximum page size for paginated queries (default=2500)                                                                                                                                                                                                                                                                      |
+| `LIGHTDASH_QUERY_RETRY_ON_TRANSIENT_ERRORS`  | When `true`, the frontend automatically retries failed queries on transient errors (5xx server responses and network errors) up to 3 times with exponential backoff (1s, 2s, 4s). 4xx client errors are never retried. Useful for instances where warehouse connections occasionally drop or the backend is briefly overwhelmed. (default=false)                                                                                                                                                                                                                                                                       |
 | `SCHEDULER_ENABLED`                          | Enables/Disables the scheduler worker that triggers the scheduled deliveries. (default=true)                                                                                                                                                                                                                                |
 | `SCHEDULER_CONCURRENCY`                      | How many scheduled delivery jobs can be processed concurrently. (default=3)                                                                                                                                                                                                                                                 |
 | `SCHEDULER_JOB_TIMEOUT`                      | After how many milliseconds the job should be timeout so the scheduler worker can pick other jobs. (default=600000, 10 minutes)                                                                                                                                                                                             |