test(agent_press): cover malformed SessionAliasRegistry JSON on load

[MarcoPorcellato]

Context

SessionAliasRegistry.load_from_disk crashes on several malformed JSON envelopes (#60). Add table-driven tests documenting current vs desired behavior.

Objectives

• Parametrize invalid payloads: nested {"aliases": {...}}, array root [], invalid JSON, non-string UUID values
• Assert either clean exception type/message or Typer-friendly error once fix(agent): handle corrupt X-Ray state files without crashing agent-write #60 is fixed
• Happy path remains covered by test_session_alias_registry_save_and_load_from_disk

Files

• tests/test_agent_press.py
• tests/test_kinetic.py (optional CLI-level agent-write with corrupt state)

Getting started

1. uv sync --all-extras && make all
2. See existing registry tests in tests/test_agent_press.py

Definition of Done

• make all passes