Pi native-process proof for https://github.com/pingdotgg/t3code/pull/20521
Reviewed/published head: cdc25d2faea98aeaedafa82f97dab474b27f6d47
Linux, Node 24, real Pi 1.3.0, isolated home, local mock OpenAI-compatible endpoint.
No authenticated account or live user data; no UI change.

Scenario: complete retained-first-prompt, SIGKILL Pi during crash-boundary prompt model request.
Resume the persisted native session through the real T3 Pi adapter with a weak reference for the interrupted turn.
After: adapter fork and rollback both leave only retained-first-prompt, excluding crash-boundary.
Root rollback: provider thread creation predates the T3 turn; recover the uncaptured wake while retaining inherited first prompt.
Before root review fix: ProviderAdapterRollbackThreadError caused by no captured session-tree entry and none found in the session tree.
After root review fix: native adapter test passes all three operations in one scoped process scenario.
Root proof at 02:27:57 UTC: 1 test passed, 1 file passed, 5.93 seconds.
Behavior assertions check the resulting JSONL user messages, not a simulated helper return.

Focused package tests: 152 passed; Pi adapter suite: 96 passed; Pi orchestration replay: 8 passed.
PR regressions: original 2 -> final 3; all fail without the fix, root also fails before review correction.
Limits: native Pi talks to a mock model endpoint; no authenticated provider, browser, macOS, Windows, iOS, Android or Electron validation.