improve(providers): add per-provider delta to quorum-mismatch warn log

[droplet-rl]

Summary

Surface the exact source of provider disagreement when the RetryProvider's quorum check fails. The existing Some providers mismatched with the quorum result or failed 🚸 warn only listed which RPC origins disagreed — operators had no signal about what differed. This PR adds a new mismatchDetails field to the warn payload mapping each mismatched provider's origin to a compact, JSON-safe delta vs the quorum result.

Per method:

• eth_getLogs — per-log onlyInA / onlyInB / differing (with fieldDiffs: { field: { a, b } }), keyed by transactionHash:logIndex. Strips the same IGNORED_FIELDS the equality check strips, so noise like blockTimestamp doesn't show up. Each bucket is capped at 5 entries with a truncated counter so payloads stay bounded even when a provider returns thousands of stale logs.
• eth_getBlockByNumber — per-key { a, b } for non-ignored fields.
• any other method — path-keyed deep diff (e.g. "receipt.logs[0].data": { a, b }).

Scope

Intentionally minimal — small, additive change to a load-bearing component:

• compareRpcResults keeps its boolean return type. No signature change, no caller updates beyond retryProvider.ts.
• RetryProvider.send keeps its current structure. The new code only adds a per-provider getMismatchDetails(values) helper alongside the existing getMismatchedProviders(values), and threads the result into the existing logQuorumMismatchOrFailureDetails call as one new field.
• Existing fields (quorumProviders, mismatchedProviders, erroringProviders) are unchanged — mismatchDetails is purely additive for log consumers.

Production code change: retryProvider.ts +37 / -6, utils.ts purely additive.

Performance

• Equal path (all-providers-agree, the hot path): zero overhead. The new code only runs inside the warn-emit branches, which only fire on mismatch or provider error.
• Mismatch path: one extra per-provider walk to build the delta. Bounded by provider count (typically 2-4) and capped output (5 entries / bucket for eth_getLogs). Fields that are equal don't appear in the output — only divergent ones.

Test plan

• yarn hardhat test test/providers/utils.test.ts — 16/16 passing (covers ignored-field handling, per-log diffs, truncation, undefined inputs, block-level diffs, generic deep diff, primitive root, type-mismatch).
• yarn lint-check — clean.
• Confirm the next real quorum mismatch in zion-across-relayer-primary carries an actionable mismatchDetails payload.