fix: compare full event paths when skipping duplicate notices

[Ali-932]

The dedup check in Framework._event_is_in_storage() compared notice paths
truncated at the first [, which erases the emitter's key and the event kind
for events emitted by keyed objects. While one such event sat deferred,
distinct events (a different instance, or a different event kind) with equal
snapshots and the same observer method were skipped as duplicates and lost.

This changes the comparison to strip only the trailing [id], matching the
intent described in the comment above it.

Added a regression test with two keyed emitters and two event kinds sharing
one observer: it fails before the change (only 1 of 3 events delivered,
assert 1 == 3) and passes after. The full test/test_framework.py suite
passes (100/100).

Fixes #2683

[benhoyt]

Rationale and logic makes sense to me, thanks for this.

[tromai]

Thank you for the fix.

I really appreciate the detailed issue write up.

[james-garner-canonical]

It looks like the intention of this logic is to defer only the first event, since we set obs.defer_next = 1 before the first emit and never touch it again. If that's correct, maybe something like this would be easier to follow:

first = len(self.seen) == 0
self.seen.append(event.handle.path)
if first:
    self.defer()

[Ali-932]

Good point, i have updated the tests.