fix(verifier): accept lifecycle state handlers

[KSHITIZ6341]

What this changes

VerifierOptions currently intersects ProxyOptions with Partial<MessageProviderOptions>. Both types declare stateHandlers with different call signatures, so TypeScript requires every verifier state handler to satisfy both the HTTP and message-provider forms. That rejects the supported { setup, teardown } lifecycle form.

This removes the redundant MessageProviderOptions intersection because ProxyOptions already carries logLevel, messageProviders, and the HTTP verifier stateHandlers. It also lets state handlers resolve without a value, matching their existing optional provider-state injection behaviour, and derives the internal setupStates return type from StateFunc.

The change is type-compatible and does not alter verifier runtime behaviour. Existing function handlers and handlers returning provider-state values remain supported.

Credit to @ghost91- for the minimal failing example, @valkolovos for tracing the conflict to the overlapping declarations, and @muratkeremozcan for supplying a standalone reproduction.

Fixes #1164

Verification

• Confirmed the regression test fails on master with TS2418 before the fix.
• biome format (228 files)
• biome lint (228 files)
• tsc --noEmit
• vitest run (28 files, 284 tests; coverage thresholds passed)
• Distribution build via rimraf dist, tsc, and copyfiles package.json ./dist
• Regression consumers (14 files, 40 passed, 2 skipped)
• Regression providers (9 files, 11 passed)
• git diff --check

No practical local test suite was omitted. The repository CI operating-system and Node.js version matrix remains to run.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.06%. Comparing base (7c332cb) to head (910c600).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1876   +/-   ##
=======================================
  Coverage   61.06%   61.06%           
=======================================
  Files          67       67           
  Lines        4187     4187           
  Branches      352      352           
=======================================
  Hits         2557     2557           
  Misses       1628     1628           
  Partials        2        2           

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