Add SSH Console Ownership Boundary (Phase 8D.4)

Implement transport-qualified session identity and immutable owner
adapters
for SSH console lifecycle and output-drain operations. Add focused host
tests
covering admission, stale identities, deferred actions, completion
races,
prompts, backpressure, and slot reuse. Update Phase 8D documentation and
current-state tracking.

docs/agent/architecture.md

@@ -157,6 +157,8 @@ admin SSH line editor ----/                              |
 
 The dispatcher is the sole caller of `esp_console_run()`, serializing UART0 and all admin SSH commands. This is required because the console registry is treated as non-reentrant, but it also means a long command or interactive prompt blocks all administration entry routes.
 
+Phase 8D.4 retains this module and exposes `admin_ssh_console_open_owned()`: copied transport-qualified slot/session/generation identity plus a firmware-lifetime immutable owner adapter. The existing two console slots are shared, not multiplied per frontend; active/executing slots cannot be replaced. Owners serialize per-session input, consume output and enforce transport liveness; completion scratch is claimed nonblockingly across owners. The existing control task calls drain/lifecycle adapters outside console locks. SSH implements its adapter and compatible admission entry point in `ssh_transport.c`, using generation-checked published snapshots and existing control APIs, never wolfSSH from the control task. `SELF_CLOSE` is owner-relative; legacy SSH actions remain SSH-specific and unsupported owner actions are rejected. No browser admin transport is yet implemented.
+
 For SSH, standard output/error is redirected to the invoking session's bounded output ring. `console_input` routes visible or hidden prompts to UART0 or the active SSH session. `exit` and Ctrl+D on an empty admin SSH line use bounded deferred self-disconnect after their acknowledgement drains; role-`user` SSH remains a binary-transparent serial stream. Session tokens include slot and generation so late queued work cannot attach to a reused SSH slot. Only the SSH owner task moves ring output through wolfSSH.
 
 Admin SSH `exit`, remote reboot, SSH stop/disconnect, and host-key rotate/reset use deferred control. The control task waits up to ten seconds for command state plus administration and transport application buffers to clear, then adds a short delay; this is a bounded best-effort heuristic, not peer-delivery confirmation. UART0 invokes these actions synchronously. User mutations and their revocations are not part of this mechanism. UART0 linenoise and the SSH editor consume the same manually maintained completion matcher and candidate formatter, so the two administration routes cannot drift in offered or displayed ambiguous completions; the hints can still drift from command registration and are not an authorization list.