The `forceFlushTranscriptBytes` path (introduced in d729ab21) bypasses the
`memoryFlushCompactionCount` guard that prevents repeated flushes within the
same compaction cycle. Once the session transcript exceeds 2 MB, memory flush
fires on every single message — even when token count is well under the
compaction threshold.
Extract `hasAlreadyFlushedForCurrentCompaction()` from the inline guard in
`shouldRunMemoryFlush` and apply it to both the token-based and the
transcript-size trigger paths.
Fixes#32317
Signed-off-by: HCL <chenglunhu@gmail.com>
