Fixes microsoft/vscode-engineering#3893.

Summary

Stabilize the terminal persistence smoke tests introduced by #323980 by separating completed-output replay from subsequent live output:

• Wait for the initial numbered output to finish before reloading the window or detaching the terminal.
• Keep the producer alive in raw input mode during reconnect, then focus the restored terminal and send a continuation line to produce the final output without shell prompt or input-echo redraws.
• Keep the strict assertion over the entire sequence, detecting missing, duplicated, or out-of-order entries without filtering them out.
• Rename the tests to describe completed-output replay and remove the arbitrary detached delay.

Why

The Windows failure in Azure build 474799 captured [21, 0, 1, ..., 99]: live output arrived before the replayed buffer. Local validation with retries disabled also reproduced a missing entry when live output raced replay.

The macOS detach/attach trace also showed that replay was complete before a wrapped shell prompt redrew over entries 95–99. Keeping the producer alive avoids returning to that prompt; raw input additionally prevents Windows console input echo from overwriting replayed output.

This is a test-only change. It verifies replay and subsequent live delivery separately rather than relying on concurrent live/replay ordering; it does not change production behavior.

Validation

• Smoke-test TypeScript compilation passed.
• Targeted hygiene and ESLint passed.
• Both Windows Insiders cases passed five consecutive runs with Mocha retries disabled: 10 passes.
• Sequence checks confirmed that duplicate, missing, and out-of-order entries still fail the assertion.
• macOS / Electron-Smoke passed on commit 49bef25: Code OSS CI.