fix: EOS run asynchronous tasks (#904)

Startup retention manager for asynchronous tasks. Handle gracefully
exceptions in these tasks or the configuration for them.

Remove tasks.py as repeated tasks are now handled by the retention
manager.

When running on GitHub, only the version date file is checked. The
development tag is merely a label, so any date set during development suffices.

The test_doc is also skipped on GitHub actions.

tests/test_databaseabc.py

@@ -787,15 +787,21 @@ class TestDbCompact:
         """Second call processes only the new window, not the full history."""
         seq = SampleSequence()
         now = to_datetime().in_timezone("UTC")
-        base = now.subtract(weeks=3)
+        # Floor to the minute to avoid sub-minute microseconds causing duplicate
+        # timestamps when interval arithmetic lands exactly on `base`.
+        now_floored = now.set(second=0, microsecond=0)
+        base = now_floored.subtract(weeks=3)
         # Dense 1-min data for 3 weeks
         _insert_records_every_n_minutes(seq, base, count=3 * 7 * 24 * 60, interval_minutes=1)
 
         seq.db_compact()
         count_after_first = seq.db_count_records()
 
-        # Add one more day of dense data in the past (simulate new old data arriving)
-        extra_base = now.subtract(weeks=3).subtract(days=1)
+        # Start 2 days before `base` and insert only 1 day worth of records,
+        # so the window [extra_base, extra_base + 1439min] stays entirely
+        # before `base - 1day` and never collides with compacted timestamps
+        # that were snapped to clean hour/15-min boundaries inside the original range.
+        extra_base = now_floored.subtract(weeks=3).subtract(days=2)
         _insert_records_every_n_minutes(seq, extra_base, count=24 * 60, interval_minutes=1)
 
         seq.db_compact()