Tutor sends students back to prewriting on reopen

# Tutor sends students back to prewriting on reopen

When a student reopens an essay document, the tutor routes them back into the prewriting step instead of resuming where they left off.

## Reproduction

Student, browser unspecified (likely Chrome on school-issued device).

1. As a student, work past the prewriting step on an essay document (into drafting or later).
2. Close the document or navigate away.
3. Reopen the same document from the documents list.
4. Observe the tutor's current step.

## Expected

The tutor resumes at the step the student last had open — drafting, revising, whatever was furthest along. Prewriting is only re-entered if the student explicitly chooses to go back.

## Actual

The tutor jumps back to prewriting, as if the document were brand-new. Student has to navigate forward again to reach their actual work.

## Impact

Hits every student who closes and reopens an essay — likely most students, since essays span multiple sessions. Reported by Kevin from observed student behavior. Not a data-loss bug (the drafting work isn't lost), but a hard friction point: students think their progress is gone, and some abandon or restart. At pilot scale (150+ students with the UA professor, plus Washington and Birmingham districts) this is a daily-cost issue. Almost certainly suppressing tutor engagement metrics.

## Affected versions

Unknown — needs an engineering pass to identify when the regression landed. Worth checking recent changes to the tutor step-resolution logic and document-open routing in `yawp-2.0`.

## Suspected cause

Best guess: the tutor's "what step is this student on?" resolver isn't reading persisted progress on document open, or is reading it but defaulting to the first step when state is ambiguous. Could also be a routing issue where the document-open path doesn't pass the resumed step through to the tutor panel.

## Workaround

Students can manually click forward through the tutor steps to get back to where they were. Annoying but not a hard block.