quak backup retries failed requests for longer (closes #165)

src/retry.ts exports UNATTENDED_RETRY_OPTIONS beside the unchanged
default: 10 attempts, a 1 s base delay and a 60 s cap, so a request that
keeps failing waits at most 243 s before it gives up. bin/quak.ts loads
the backup's session with them, so its refresh, ML data and downloads
all use them; every other command keeps the default. What is retried
and the backoff formula are unchanged.

Model: opus-5-5

README.md

@@ -432,8 +432,8 @@ With the defaults a file that is going to fail gives up after at most three and
 a half seconds of waiting. `quak backup` usually runs from cron with nobody
 watching, so every request it makes uses the second column instead, exported as
 `UNATTENDED_RETRY_OPTIONS`: a request that keeps failing gives up after at most
-243 seconds, about four minutes, of waiting, so an outage of a few minutes does
-not fail files until the next run. Every other command uses the defaults. A
+243 seconds of waiting, and usually after about half that, since each wait is
+drawn at random below its ceiling. Every other command uses the defaults. A
 library user gets the same budget by passing `UNATTENDED_RETRY_OPTIONS` as
 `ApiClientOptions.retry`. `sleep` and `random` are injectable through the same
 option, which is how the test suite exercises the whole policy without waiting.

src/retry.ts

@@ -37,9 +37,9 @@ export const DEFAULT_RETRY_OPTIONS: ResolvedRetryOptions = {
     random: Math.random,
 };
 
-// For a run nobody is watching, such as `quak backup` from cron: it rides out
-// an outage of a few minutes instead of failing every file until the next run.
-// A request that keeps failing waits at most 243 s in all before it gives up.
+// For a run nobody is watching, such as `quak backup` from cron. A request that
+// keeps failing waits at most 243 s in all before it gives up, usually about
+// half that, since each wait is drawn at random below its ceiling.
 export const UNATTENDED_RETRY_OPTIONS: ResolvedRetryOptions = {
     ...DEFAULT_RETRY_OPTIONS,
     attempts: 10,