Close Phase 8D.4 validation

The user confirmed successful empty-Enter and soak testing, closing
8D.4 while leaving numeric reserve gates open and advancing the next
planned work to 8D.5.

docs/agent/current-state.md

@@ -4,6 +4,10 @@ This file is working memory. Update it during active work and before handoff; do
 
 ## Development state
 
+- **8D.4 validated by explicit user sign-off (2026-09-06):** User confirms successful empty Enter and soak testing and explicitly closes Phase 8D.4. This supersedes older pending/in-progress notes below, including the 8D.3 empty-Enter target retest. Boot/full-client-mix evidence and sign-off are in `docs/phase8d4_implementation.md`. Exact soak duration/revision, post-soak/cleanup telemetry and other detailed checklist results were not supplied; these are evidence limitations, not blockers to the user-approved closure or claims of execution. Numeric reserves remain open. No new build/device operation for sign-off. Wait for a separate **8D.5** request; no browser admin backend or M2 completion is claimed.
+
+- **8D.4 target validation in progress (2026-09-06):** User supplied clean-boot/full-client-mix UART0 evidence, recorded in `docs/phase8d4_implementation.md`. Loaded internal/DMA/PSRAM free **34,632 / 26,876 / 8,089,284 B**, minima **20,648 / 12,892 / 8,077,516 B**, largest **25,600 / 25,600 / 7,995,392 B**; SSH stack minimum-free **16,280 B** (boot **18,472 B**). Four broker clients at 115200 baud: SSH writer, USB and two web observers; user/admin SSH and both browser roles admitted successfully, no reported I/O/transport failures. One cumulative SSH broker revocation retained without diagnosis. Exact flashed revision/duration not supplied. Console-specific regressions, lifecycle/soak/cleanup and explicit phase sign-off remain pending; numeric reserves remain open. No 8D.5 request or implementation.
+
 - **8D.4 implemented / host-tested / build-verified (2026-09-06), target pending:** User separately requested the small console boundary. Added transport-qualified identity and immutable output-drain/lifecycle owner callbacks in `admin_ssh_console`, retained the SSH admission API in `ssh_transport`, and kept two shared slots, one dispatcher and all capacities/stacks. Shared completion scratch now has nonblocking ownership; occupied-slot replacement and deferred input fail closed. `python3 tests/admin_console_boundary/run.py` and existing policy suite pass; independent review found no defects. `pio run` passes in **43.61 s**, **95,084 B RAM / 1,627,173 B flash** (**-424 / +1,448 B** versus recorded latest 8D.3). See `docs/phase8d4_implementation.md` for contracts, host-test limits, accounting and target checklist. No browser admin routes, uploads or 8D.5 work. Prior M1 sign-off stands; numeric reserves and 8D.4 target regression remain pending. Stop for validation/user decision before separately requested 8D.5.
 
 - **8D.3/M1 completed by explicit user sign-off (2026-09-06):** User closes M1 after post-soak evidence, superseding all older pending/blocked/in-progress statements below. Four broker clients remain active at 115200 baud (SSH writer; USB/two web observers), both SSH routes and two cookie sessions active. Post-soak internal/DMA/PSRAM free **38,656 / 30,900 / 8,138,320 B**, minima **13,756 / 6,000 / 8,072,744 B**, largest **25,600 / 25,600 / 7,995,392 B**; SSH stack minimum-free **16,288 B**. Minima/largest unchanged from earlier loaded sample; no reported transport failures. Record/evidence limits in `docs/phase8d3_implementation.md`. Sample is still connected, not disconnected cleanup; exact soak duration/revision not supplied. Unrecorded detailed checks do not reopen signed-off M1 or become claims of execution. Numeric reserves remain open; empty-Enter fix target retest remains unrecorded separately. **Wait for a separate 8D.4 request; no M2 implementation performed.**