First successful flash: placeholder face live; fix 20MHz PSRAM trap; power ladder

- firmware boots to a rendered LVGL face in 1.57s (eyes + smile + tag)
- sdkconfig: CONFIG_IDF_EXPERIMENTAL_FEATURES=y unlocks SPIRAM 200MHz
  (silently degraded to 20MHz before -> MIPI-DSI underrun -> LVGL lock
  starvation -> task watchdog); mirrors official 08_lvgl_demo_v9 config
- architecture.md: power management section (user prime concern) —
  active/ambient/dormant/night ladder, levers, hard edges, <=300ms wake
- AGENTS/CLAUDE: replace stale bring-up warnings with verified commands

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

firmware/main/desklock_main.c

@@ -6,25 +6,55 @@
  *   2. Wi-Fi up via ESP32-C6 (ESP-Hosted over SDIO)
  *   3. WebSocket connection to the DeskLock gateway
  *   4. Face state machine: idle / listening / thinking / speaking
+ *
+ * Current stage: bring-up — display + a placeholder face.
  */
 
 #include "esp_log.h"
 #include "bsp/esp-bsp.h"
+#include "lvgl.h"
 
 static const char *TAG = "desklock";
 
+static void show_placeholder_face(void)
+{
+    bsp_display_lock(0);
+
+    lv_obj_t *scr = lv_screen_active();
+    lv_obj_set_style_bg_color(scr, lv_color_black(), 0);
+
+    lv_obj_t *eyes = lv_label_create(scr);
+    lv_label_set_text(eyes, "-   -");
+    lv_obj_set_style_text_color(eyes, lv_color_hex(0xADFFC8), 0);
+    lv_obj_set_style_text_font(eyes, &lv_font_montserrat_48, 0);
+    lv_obj_align(eyes, LV_ALIGN_CENTER, 0, -80);
+
+    lv_obj_t *mouth = lv_label_create(scr);
+    lv_label_set_text(mouth, "\\_/");
+    lv_obj_set_style_text_color(mouth, lv_color_hex(0xADFFC8), 0);
+    lv_obj_set_style_text_font(mouth, &lv_font_montserrat_48, 0);
+    lv_obj_align(mouth, LV_ALIGN_CENTER, 0, 40);
+
+    lv_obj_t *tag = lv_label_create(scr);
+    lv_label_set_text(tag, "DESKLOCK");
+    lv_obj_set_style_text_color(tag, lv_color_hex(0x2F7A4B), 0);
+    lv_obj_align(tag, LV_ALIGN_CENTER, 0, 160);
+
+    bsp_display_unlock();
+}
+
 void app_main(void)
 {
     ESP_LOGI(TAG, "DeskLock starting");
 
     bsp_display_start();
     bsp_display_backlight_on();
+    show_placeholder_face();
 
-    /* TODO(bring-up): render placeholder face via LVGL
-     * TODO(bring-up): Wi-Fi via ESP-Hosted (C6)
-     * TODO(voice): mic capture (ES7210) -> WebSocket upstream
-     * TODO(voice): gateway PCM downstream -> ES8311 playback
+    ESP_LOGI(TAG, "DeskLock up (placeholder face)");
+
+    /* TODO(face): full LVGL face state machine per docs/architecture.md
+     * TODO(net): Wi-Fi via ESP-Hosted (C6), WebSocket to gateway
+     * TODO(voice): ES7210 capture upstream, ES8311 playback downstream
      */
-
-    ESP_LOGI(TAG, "DeskLock up (display only)");
 }

firmware/sdkconfig.defaults

@@ -5,10 +5,19 @@ CONFIG_IDF_TARGET="esp32p4"
 CONFIG_ESPTOOLPY_FLASHSIZE_32MB=y
 CONFIG_PARTITION_TABLE_SINGLE_APP_LARGE=y
 
-# 32 MB in-package PSRAM (hex mode) — LVGL frame buffers live here
+# PSRAM at 200 MHz — REQUIRED for the 800x800 MIPI-DSI framebuffer.
+# 200 MHz is gated behind IDF_EXPERIMENTAL_FEATURES; without it the build
+# silently falls back to 20 MHz and the DSI underruns (mirrors the official
+# 08_lvgl_demo_v9 example config).
 CONFIG_SPIRAM=y
-CONFIG_SPIRAM_MODE_HEX=y
+CONFIG_IDF_EXPERIMENTAL_FEATURES=y
 CONFIG_SPIRAM_SPEED_200M=y
+CONFIG_SPIRAM_XIP_FROM_PSRAM=y
+CONFIG_CACHE_L2_CACHE_256KB=y
+CONFIG_CACHE_L2_CACHE_LINE_128B=y
 
 CONFIG_COMPILER_OPTIMIZATION_PERF=y
 CONFIG_FREERTOS_HZ=1000
+
+# LVGL font for the bring-up placeholder face
+CONFIG_LV_FONT_MONTSERRAT_48=y