test(pi): hold packaged rpc confirmation past timeout

.project-docs/30-worklog/tasks/20260825-pi-background-run-lease-6a4e2c91.md

@@ -204,6 +204,15 @@ Follow-up plan from cumulative HEAD `621ebb17810394f6f7b97154cb01217bc9112857`:
   runtime failure. The proof was corrected to arm prompt and compact delay
   explicitly through E2E-only Main seams, removing message-shape dependence;
   this was a proof-wiring failure, not a product fallback or relaxed gate.
+- The explicit Provider arm then proved the loopback HTTP response remained
+  open for 12 seconds, but locked Pi acknowledged the local prompt RPC before
+  the first Provider response on this controlled path. The proof therefore
+  separates the two facts instead of claiming causality: the Provider response
+  remains delayed for 12 seconds, and an E2E-only one-shot Pi RPC response hold
+  independently crosses the 10-second client threshold. The hold is armed only
+  through the existing Main fault-injection surface, is absent from Renderer
+  and product configuration, and preserves the real packaged Pi command,
+  session, Provider request, events, and cleanup path.
 
 - `pnpm install --frozen-lockfile` — passed with package-manager-pinned pnpm
   `10.33.4` and locked Pi `0.84.2`.