Task: Add stress scenarios for resize storms, incomplete escapes, oversized paste, and mailbox pressure

[RtlZeroMemory]

Parent EPIC: #324

Problem:

Some TUI failures only show up under pressure or malformed input sequences, not normal interaction flows.

Scope:

• Add deterministic scenarios for resize storms, incomplete escape handling, oversized paste, and mailbox pressure.
• Assert absence of wedges, corrupted state, and hidden failure loops.
• Keep these scenarios deterministic enough for CI use where appropriate.

Done when:

• The listed pressure and malformed-input scenarios exist.
• They check for safe behavior rather than just lack of crashes.

Notes:

• This task should produce work that is reviewable against expected behavior, not current implementation shape.
• Keep outputs straight to the point and tied to repo code or repo process.

[RtlZeroMemory]

Implemented in #367.

Added deterministic stress coverage for:

• resize storms in the PTY scenario suite
• incomplete escapes in the PTY scenario suite
• oversized paste in the terminal I/O contract slice
• repeated SAB mailbox pressure in worker integration

This now pins:

• resize storms and incomplete escapes do not wedge later interaction
• oversized paste is dropped without wedging the stream
• repeated mailbox pressure drains without a fatal loop and the backend still accepts a later frame

Verified with:

• node --test packages/node/dist/__tests__/worker_integration.test.js
• node --test packages/node/dist/__tests__/ptyScenario.test.js
• node --test packages/node/dist/__e2e__/terminal_io_contract.e2e.test.js

Still unresolved:

• no new visible widget oracle was added for mailbox pressure; this slice remains backend-behavior focused