fix: re-attach the original openai wire system on rebuild (kernel system hoist)

[ranxianglei]

Symptom

Restart on provider-mode openai wire (glm-5.3 etc.): pre-restart panel shows blocks; post-restart panel shows Blocks: none, Sent-to-LLM balloons 146k → 546k, all ranges reappear uncompressed. Blocks only re-materialize at the first provider request. Additionally: after any compression covering the first span, rebuilt payloads lose the system prompt entirely (live wire systemLen 45151 → 0).

Root cause

The openai wire's leading system message sat INSIDE the fold id space (it took m00001). System content is host runtime state — live 45k chars vs ~7.4k reconstruction across restarts — so:

1. every span fingerprint derived from a restart's reconstruction mismatched → the guard rejected every in-stream replay → "Blocks: none" until the first wire fold;
2. a compression covering m00001..m000xx ate the system piece → rebuilt payloads carried no system at all.

anthropic (top-level system) and responses (instructions) never had this — openai was the odd codec folding system into the id space.

Fix (with acp-kernel 0.0.37)

Kernel PR ranxianglei/acp-kernel#120 hoists the contiguous leading system/developer prefix out of the openai fold space; openaiToCore now returns { msgs, systemText }. This PR:

• payloadToCore carries systemText from the kernel hoist
• NEW restoreOpenaiSystemPrefix(originalMessages, rebuilt): re-attaches the ORIGINAL contiguous leading system/developer messages from the wire verbatim (roles / count / name fields byte-for-byte), mirroring the anthropic top-level system path — never the reconstruction
• rebuild wiring in src/index.ts composes fidelity-restore + system-restore

Tests

• updated 2 old-contract tests (wire-transform, wire-fidelity range off-by-one)
• NEW e2e restart regression: live wire system carries runtime injections the restart cannot reproduce (glm-5.3-like); asserts the block survives post-restart pre-LLM AND the original injected system rides every rebuilt payload
• 261 pass / 0 fail, tsc clean, acp-kernel 0.0.37 from npm