Scheduled searches with a weekly review of new and rising repositories

A search can now be saved with a schedule (every N hours, daily, or weekly at
a given day and time). An internal scheduler runs it and keeps a snapshot of
the results on a /data volume (JSON files, no new dependency). The new Watch
tab lists the scheduled searches; the review page of each one shows, for any
run of its history, the repositories never seen before and the ones that
gained the most stars since the previous run.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.env.example

@@ -5,3 +5,6 @@ GITHUB_TOKEN=
 CACHE_TTL=5m
 AUTH_USER=
 AUTH_PASS=
+# Time zone of the scheduled searches.
+TZ=Europe/Paris
+HISTORY_KEEP=100