[Assertions] Current expect is too permissive, refactor it.

[priyanshus]

What happened?

Currently, expect is too permissive. Because MatcherChain is generic over EvalInput and contains all possible matchers, TypeScript allows:

await expect("just a string").toBeFaithful();

However, This should always be taking query, context, and response to run the assertion.

Above will crash on run time because as below piece of code checks for query.

// packages/assertions/src/expect/expect.ts:74

if (!input.query) {
  throw new EvaliphyError(
    EvaliphyErrorCode.INVALID_ASSERTION_INPUT,
    "toBeFaithful requires a query..."
  );
}

Acceptance Criteria:

• Update tests, add new tests
• Update docs, update website
• Update prompts and text assertions to use only one variable

Reproduction steps

No response

Evaliphy version

No response

Relevant log output