fix: increase download retry attempts and backoff for transient GitHub outages

The CI image build (run 3597) failed because install_tools._download
exhausted its 3 retry attempts on RemoteDisconnected errors from
GitHub releases. The max backoff of 10s was too short for sustained
transient outages.

- Increase MAX_DOWNLOAD_RETRIES from 3 to 5
- Increase max backoff from 10s to 30s

DEVX-158

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

src/devx/tools/install_tools.py

@@ -50,8 +50,9 @@ logger = logging.getLogger(__name__)
 # GitHub releases occasionally drops connections ("Remote end closed
 # connection without response"). Retrying with backoff before falling
 # through to the next fallback URL makes the build resilient to
-# momentary network blips.
-MAX_DOWNLOAD_RETRIES = 3
+# momentary network blips. 5 attempts with up to 30s between retries
+# handles sustained transient outages (observed in CI image builds).
+MAX_DOWNLOAD_RETRIES = 5
 
 ACTIONLINT_VERSION = "1.7.12"
 
@@ -96,7 +97,7 @@ def _download(url: str, dest: Path, *, _sleep=None) -> None:
     """
     retrying = Retrying(
         stop=stop_after_attempt(MAX_DOWNLOAD_RETRIES),
-        wait=wait_exponential(multiplier=2, min=2, max=10),
+        wait=wait_exponential(multiplier=2, min=2, max=30),
         retry=retry_if_exception_type((urllib.error.URLError, OSError, ConnectionError)),
         before_sleep=before_sleep_log(logger, logging.WARNING),
         sleep=_sleep if _sleep is not None else time.sleep,