Move console payloads to lazy PSRAM storage

docs/agent/architecture.md

@@ -224,6 +224,7 @@ Hardware diagnostics are synchronous console commands. RS-232 tests own the phys
 - Password authentication performs PBKDF2 outside the user-database mutex and revalidates afterward. Some password mutation paths currently derive verifiers while holding the mutation lock; do not generalize the authentication locking pattern without checking the exact path.
 - Avoid holding service/database/broker locks across I2C, network sends, or other potentially long operations unless the existing contract explicitly requires it. Preserve the existing broker-before-serial lock order.
 - Serial RX/TX stream payloads, broker per-client payloads, the transactional user-database candidate, and selected cryptographic allocations prefer PSRAM with internal fallback. The live user database, FreeRTOS control structures, UART driver buffers, and task stacks remain internal where deterministic/cache-disable access matters.
+- Ping's 21-event payload (4,200 bytes) and the public user-console snapshot (2,156 bytes) are lazy PSRAM-only allocations retained for firmware lifetime, with no internal fallback. Queue control and synchronization stay internal; only ping or user status/list/show fails on allocation failure, never registration, mutations or UART0 recovery. Commands retain dispatcher/gate serialization; ping callbacks are task-context producers. The entire user snapshot is wiped after each display attempt. Never introduce ISR/cache-off access or free payloads while callbacks can retain them. Regression coverage: `tests/admin_console_boundary/psram_ping.py` and `accounts.py`.
 - The build disables wolfSSL ESP32 AES/SHA acceleration, and the HTTPS path uses software AES for PSRAM-backed records. This preserves the validated workaround for uncoordinated mbedTLS/wolfSSL hardware-crypto locks and a prior mbedTLS external-RAM DMA watchdog stall.
 
 ## Legacy credential removal storage boundary