Fix native Hermes live delta accumulation

[p697]

Hermes live replies were replacing the accumulated body with the latest fragment. The Bridge sends incremental chat.delta.message.content, while the native mapper treated every chat delta as a complete snapshot. Map only Hermes fragments to .delta and keep snapshot identity absent; OpenClaw cumulative snapshots, full finals and SDK text modes retain their existing behavior.

Six pure package tests (eight parameterized cases) cover the actual producer-shaped synthetic envelopes, whitespace and Unicode bytes, Direct/Relay mapping, tool boundaries, full/final-only snapshots and source-metadata isolation. Only Hermes raw fragments bypass the cumulative silent-prefix filter, so NO + RMAL remains NORMAL; full-final, OpenClaw, SDK and subagent filtering stays unchanged. One actual app regression feeds SessionEvents.map directly into NativeLiveMessages to verify a single segment's intermediate accumulated body, stable render UUID and corrected whole final replacement. Multi-segment aggregate-final reconciliation remains unchanged and is explicitly not claimed. App report minimum is 315, including a 314-case rejection.

Validation:

• git diff --check passed.
• Production source 653895db: the new package file passed all six methods/eight cases; the actual new mapper-to-consumer app case passed 1/1. The dual-architecture development build compiled all 315 app methods. No full local app suite ran.
• Docs: 16 instruction pairs/seven regressions; report validator: three regressions passed. Exact-head full CI runs on this PR.
• The signed QA development app, Swift modules, matching dSYMs and source map are preserved privately for follow-up debugging. The owned app stopped, QA simulator shut down and leases were released; the exact guarded synthetic document retained its three draft references, empty draft and held item without queued/sending items.
• The generic failure alert and real Stop acceptance remain separate, unresolved work. No Bridge, React Native default, shared service, protocol, credential, version or release changes.