fix: scope getDynamicEmail to referenced placeholder (fixes #53)

[rishishanbhag]

Summary

Fixes #53 by scoping getDynamicEmail to the dynamic email placeholder the step set actually references, instead of always preferring the global inbox whenever executionId is set.

Problem

When runSteps was called with an executionId, getDynamicEmail() always returned {{global.dynamicEmail}} — even if the steps only used {{run.dynamicEmail}}.

Root cause:

• generateGlobalValues() always creates a {{global.dynamicEmail}} when an email domain is configured and executionId is present.
• getDynamicEmail used globalValues?.["{{global.dynamicEmail}}"] || localValues["{{run.dynamicEmail}}"], so the global value was always truthy and the run-scoped fallback was never used.
• As a result, {{email.extract(...)}} (e.g. {{email.otp:get the OTP}}) queried the wrong inbox — the shared global address instead of the run-specific one filled in earlier in the same runSteps call.

Solution

Introduced a reference-based preference computed from the raw steps and assertions before placeholder substitution:

Step set references | dynamicEmailPreference | Inbox used for {{email.extract(...)}} -- | -- | -- {{global.dynamicEmail}} | "global" | Shared execution inbox Only {{run.dynamicEmail}} | "run" | Fresh per-call inbox (fixes the bug) Neither | "auto" | Global if available (preserves cross-call OTP flows)

Changes

src/data-cache.ts

• Added DynamicEmailPreference type and computeDynamicEmailPreference() to scan steps/assertions for {{run.dynamicEmail}} and {{global.dynamicEmail}}.
• processPlaceholders() now returns dynamicEmailPreference alongside processed steps and values.
• getDynamicEmail() accepts a third preference argument and routes to the correct inbox.

src/index.ts

• Threads dynamicEmailPreference from processPlaceholders into getDynamicEmail in the per-step loop.
• Removed the stale ~~~ This logic needs to be fixed ... comment.

src/__tests__/data-cache.test.ts

• Added tests for computeDynamicEmailPreference, updated getDynamicEmail tests for all three preference modes, and added processPlaceholders coverage for run-only, global, and no-reference step sets.

[rishishanbhag]

Hey @panda-sandeep @unclebay143 , would you mind reviewing this when you get a chance? Fixes #53