chore(sdk): reload_from_storage emits an EventsOrigin::Cache

[Hywan]

This patch updates
PinnedEventCacheStateLockWriteGuard::reload_from_storage. It calls notify_subscribers with EventsOrigin::Sync. This patch changes for EventsOrigin::Cache. All events are indeed loaded from the store, so the cache.

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• I've documented the public API Changes in the appropriate CHANGELOG.md files.
• This PR was made with the help of AI.

[poljar]

All events are indeed loaded from the store, so the cache.

So the cache!?!? The cache what? 😅

Is this fixing a bug? Do we want a regression tests for such a bug?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.82%. Comparing base (dab87b7) to head (a212378).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6451      +/-   ##
==========================================
- Coverage   89.84%   89.82%   -0.03%     
==========================================
  Files         378      378              
  Lines      104337   104337              
  Branches   104337   104337              
==========================================
- Hits        93746    93723      -23     
- Misses       7000     7017      +17     
- Partials     3591     3597       +6     

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[codspeed-hq]

Merging this PR will not alter performance

✅ 50 untouched benchmarks

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_{Comparing Hywan:chore-sdk-event-cache-pinned-evnts-reload-from-storage-events-origin (a212378) with main (63f5be6)}