fix opencode e2e tests

[squishykid]

Entire-Checkpoint: f2cf04c438d8

https://github.com/entireio/cli/actions/runs/22437583923/job/64971337382

[cursor]

PR Summary

Low Risk
Low risk: changes are confined to e2e test utilities and test timing, reducing flakiness without affecting production logic.

Overview
Fixes flakiness in TestInteractiveContentOverlapRevertNewFile by adding an explicit wait for the interactive session to transition ACTIVE → IDLE before the test overwrites and commits docs/red.md.

Introduces testutil.WaitForSessionIdle, which polls .git/entire-sessions/*.json for any session still in phase active, addressing a race where the prompt can render before the turn-end hook completes (notably with OpenCode).

^{Written by Cursor Bugbot for commit c54d1ea. Configure here.}

[Copilot]

Pull request overview

This PR addresses flakiness in OpenCode-driven e2e tests by adding a synchronization point that waits for interactive sessions to fully complete their turn-end hook work before proceeding with user-driven file edits/commits.

Changes:

• Added a new e2e test helper that polls .git/entire-sessions/*.json until no session is in "active" phase (or times out).
• Updated an interactive e2e test to call the new helper after the agent prompt completes, mitigating a TUI-prompt-vs-hook-execution race.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
e2e/testutil/assertions.go	Adds WaitForSessionIdle to poll session state files and block until sessions are no longer active.
e2e/tests/existing_files_test.go	Uses WaitForSessionIdle to stabilize TestInteractiveContentOverlapRevertNewFile before overwriting and committing.