WIP: feat(native): introduce WER mode for better WER interop

[jpnurmi]

Allow configuring whether SEH and fast-fail crashes propagate to WER.

[sentry]

Bug: The SEH crash handler crash_exception_filter unconditionally returns EXCEPTION_CONTINUE_SEARCH, ignoring the wer_mode for SENTRY_WER_MODE_EXCLUSIVE and SENTRY_WER_MODE_NONE.
_{Severity: HIGH}

Suggested Fix

Add logic to the crash_exception_filter function to check ctx->wer_mode. It should return EXCEPTION_EXECUTE_HANDLER for SENTRY_WER_MODE_EXCLUSIVE and SENTRY_WER_MODE_NONE, and EXCEPTION_CONTINUE_SEARCH for SENTRY_WER_MODE_SHARED.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: include/sentry.h#L1140-L1146

Potential issue: The SEH crash handler in `src/backends/native/sentry_crash_handler.c`,
specifically the function `crash_exception_filter`, unconditionally returns
`EXCEPTION_CONTINUE_SEARCH`. This contradicts the documented behavior for
`SENTRY_WER_MODE_EXCLUSIVE` and `SENTRY_WER_MODE_NONE`, which require the function to
return `EXCEPTION_EXECUTE_HANDLER` to prevent Windows Error Reporting (WER) from
processing the crash. The implementation fails to check the `ctx->wer_mode`, thus
violating the API contract and causing incorrect WER interop behavior for SEH crashes on
Windows.

_{Did we get this right? 👍 / 👎 to inform future reviews.}