* fix: include ACP sessions in default search sources
* fix: remove hardcoded source allowlist from session search
The default source_filter was a hardcoded list that silently excluded
any platform not explicitly listed. Instead of maintaining an ever-growing
allowlist, remove it entirely so all sources are searched by default.
Callers can still pass source_filter explicitly to narrow results.
Follow-up to cherry-picked PR #1817.
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Co-authored-by: someoneexistsontheinternet <154079416+someoneexistsontheinternet@users.noreply.github.com>
Co-authored-by: Test <test@test.com>