Adds comprehensive tests to prevent regression of issue #3165 where
repost notifications were incorrectly blocked by home feed deduplication.
Tests cover:
- Regression test: notifications not blocked by home dedup (main fix)
- Home feed deduplication still works correctly
- Dedup tracks inner event ID, not repost event ID
- Context isolation (.other context doesn't affect dedup)
Each test documents the expected behavior and provides clear failure
messages to aid debugging if the bug reoccurs.
Signed-off-by: alltheseas
Signed-off-by: William Casarin <jb55@jb55.com>
