test(openclaw): cover Session Sentry event field fallbacks

[cursor]

Risky behavior now covered

• OpenClaw message_sending events that provide outbound text via text instead of content are still scanned by Session Sentry.
• Session identity fallback across conversationId and session_id is preserved when conversation_id is absent, preventing accidental counter merging under default.

Test files added/updated

• openclaw-plugin/test/session_sentry.test.ts

Why this reduces regression risk

These tests lock down compatibility with multiple OpenClaw event shapes used by the Session Sentry hook. A regression in these fallbacks could silently skip multi-turn exfil scanning or collapse unrelated conversations into the same risk counter.

Validation

• npm test -- session_sentry.test.ts (15 passed)
• npm test in openclaw-plugin (24 passed)

Note: npm ci reported engine warnings because the environment has Node v22.14.0 while some OpenClaw dependencies declare >=22.19.0; tests still passed.