# Fix Web Terminal Resilience — Tasks

## Review Workload Forecast

| Field | Value |
| ------- | ------- |
| Estimated changed lines | 180–280 |
| 400-line budget risk | Low |
| Chained PRs recommended | No |
| Suggested split | Single focused change |
| Delivery strategy | single-pr |
| Chain strategy | feature-branch-chain |

Decision needed before apply: No
Chained PRs recommended: No
Chain strategy: feature-branch-chain
400-line budget risk: Low

## Tasks

- [x] **RED — backend input/control concurrency:** characterize a PTY write that waits for readiness while an acknowledgement is received; prove the acknowledgement is handled without waiting for that write to finish.
- [x] **GREEN — ordered input writer:** move PTY writes behind one cancellable ordered queue/worker while retaining the current public WebSocket message protocol and input ordering.
- [x] **TRIANGULATE — lifecycle:** cover worker cancellation and queued-write failure/disconnect handling.
- [x] **RED — frontend socket ownership:** characterize stale close/retry callbacks after a newer socket has become current.
- [x] **GREEN — reconnect ownership:** ensure only the current socket can update state or schedule a retry; cancel retry timers during cleanup.
- [x] **REFACTOR:** keep the connection lifecycle readable and avoid changing the intentional desktop scrollback configuration.
- [x] **Verify:** run targeted backend and frontend tests, frontend typecheck/lint/build, backend checks practical in the isolated worktree, and inspect diagnostics. (Backend pytest is unavailable locally: no pytest/uv executable; Docker test execution was explicitly declined.)