Background

WT-18626 fixed a stale-image bug where the disaggregated victim cache cached page->dsk under a block_meta that already described a newer reconciled image. PR #14717 added a Catch2 test for the image-resolution helper __evict_page_disagg_image().

Goal

Add a put-level Catch2 unit test that drives __evict_page_victim_cache() with a mocked WT_PAGE_LOG_HANDLE::plh_cache_put (and plh_cache_available) so we can assert the exact buffer, size and metadata passed to the block cache for each reconciliation-result state:
* no reconciliation result → page->dsk cached
* WT_PM_REC_REPLACE with retained image → mod_disk_image cached
* WT_PM_REC_REPLACE without retained image, WT_PM_REC_MULTIBLOCK, WT_PM_REC_EMPTY → nothing cached

Notes

Mocking the page-log / block-cache layer may require adding a test-only page-log handle or extending existing test helpers. This is likely a larger piece of work than the helper-level test.

Acceptance Criteria* New Catch2 test under test/catch2/misc_tests/ registered in test/catch2/CMakeLists.txt.

• Test fails when the cache put uses page->dsk or the wrong image_size, and passes with the WT-18626 fix.
• Ticket linked to WT-18626 as "Relates to".