fix(nexusmutual): capital_pool_mcr stale since 2025-10-30 (MCR merged into new Pool contract)

[rmelbardis]

Bug fix: nexusmutual_ethereum.capital_pool_mcr has served a stale MCR value since 2025-10-30.

In Nexus Mutual's 2025-10-30 release, the standalone MCR contract (0xcafea92739e411a4d95bbc2275ca61de6993c9a7) was retired and MCR logic moved into the new Pool proxy. The event signature is unchanged (topic0 0x6e87c25e322c4ad68faf7916d0788baaf714d806fe887a84ee4b84ad9666f686) and is already decoded as nexusmutual_ethereum.Pool_evt_MCRUpdated, but the spell only reads the retired contract's tables, so its forward-fill repeats the 2025-10-30 value indefinitely.

Expected value (block explorer): https://etherscan.io/address/0xcafea91714e55756c125b509274ede9bc91697cb#events — latest MCRUpdated (2026-08-20) has mcr ≈ 10,176.8 ETH.
Incorrect value (Dune): select max(block_date), max_by(mcr_eth_total, block_date) from nexusmutual_ethereum.capital_pool_mcr → stuck at 7,556.6 ETH (~26% understated).
Scale: every row since 2025-10-30 (~300 days); feeds the MCR and MCR% charts on the Nexus Mutual Capital Pool dashboard.

Fix: add Pool_evt_MCRUpdated as a third union branch in mcr_events (identical column names) and register the source.

[cursor]

PR Summary

Low Risk
Narrow dbt source/union change for a downstream analytics view; no auth, funds, or protocol logic. Downstream MCR/MCR% figures will change for dates after 2025-10-30.

Overview
Stops nexusmutual_ethereum.capital_pool_mcr from forward-filling a stale MCR after Nexus Mutual moved MCR updates off the retired MCR contract (2025-10-30).

Adds a third mcr_events union on Pool_evt_MCRUpdated (same columns as MCR_evt_MCRUpdated) and registers that source so daily MCR totals pick up post-merge events.

^{Reviewed by Cursor Bugbot for commit cd3364d. Configure here.}

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[rmelbardis]

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