Update remaining docs for the second panel/board (missed in the previous commit)

docs/hardware.md and firmware/README.md were updated already; this
catches the root README, docs/architecture.md, docs/widgets.md, and
server/README.md -- all still described the project as single-panel/
single-chip (800x480, ESP32-C6 only) even after image_pipeline.py
stopped hardcoding that.

README.md

@@ -1,9 +1,12 @@
 # ESPresso Frame
 
-A DIY e-ink photo frame: an ESP32-C6 pulls photos from your
-[Immich](https://immich.app) library and displays them on a 7.3" full-color
+A DIY e-ink photo frame: an ESP32 board pulls photos from your
+[Immich](https://immich.app) library and displays them on a full-color
 e-paper panel, waking on a timer to refresh and spending the rest of its
-time in deep sleep.
+time in deep sleep. The original build is a 7.3" panel on an ESP32-C6;
+a larger 13.3" panel on Seeed's EE02 (ESP32-S3) is supported
+server-side, but its firmware driver isn't working yet -- see
+[`docs/hardware.md`](docs/hardware.md).
 
 - **No cables to a computer, no SD card shuffling.** Provisioning is a
   captive portal with a QR code drawn on the panel itself -- scan, join,
@@ -12,7 +15,9 @@ time in deep sleep.
   all the work (pulling from Immich, cropping, dithering, packing into
   the panel's exact pixel format) and hands the device a stream it can
   write straight to SPI. The ESP32-C6 has no PSRAM and not much SRAM to
-  spare -- keeping it a dumb display client is what makes that workable.
+  spare -- keeping it a dumb display client is what makes that workable
+  (the same design carries over to the ESP32-S3 board even though it
+  does have PSRAM, for consistency).
 - **Crops toward faces, not just the center**, using face bounding boxes
   Immich already computed for its own People feature -- no bundled face
   detector.
@@ -21,8 +26,13 @@ time in deep sleep.
 
 ## Hardware
 
-- ESP32-C6 dev board (8MB flash)
-- [Waveshare 7.3" E Ink Spectra 6 (E6)](https://www.waveshare.com/7.3inch-e-paper-hat-e.htm) panel -- 800x480, 6-color, SPI
+- ESP32-C6 dev board (8MB flash), or Seeed's XIAO ESP32-C6 (production
+  board) -- both drive the panel below.
+- [Waveshare 7.3" E Ink Spectra 6 (E6)](https://www.waveshare.com/7.3inch-e-paper-hat-e.htm) panel -- 800x480, 6-color, SPI.
+- Experimental, not yet working: [Waveshare 13.3" E Ink Spectra 6](https://www.waveshare.com/13.3inch-e-paper-hat-plus-e.htm)
+  (1600x1200) on [Seeed's EE02](https://www.seeedstudio.com/XIAO-ePaper-DIY-Kit-EE02-for-13-3-Spectratm-6-E-Ink.html)
+  (ESP32-S3) -- server-side support exists, but the firmware driver's
+  panel init sequence isn't ported from vendor code yet.
 
 See [`docs/hardware.md`](docs/hardware.md) for wiring,
 [`docs/architecture.md`](docs/architecture.md) for how the two halves talk
@@ -34,14 +44,14 @@ placeable photos/calendar/whiteboard widget system.
 1. **[`server/`](server/)** -- run the FastAPI server first (Docker
    Compose, points at your Immich instance). See
    [`server/README.md`](server/README.md).
-2. **[`firmware/`](firmware/)** -- build and flash the ESP32-C6, then
+2. **[`firmware/`](firmware/)** -- build and flash the board, then
    scan the QR codes it draws on first boot to provision it. See
    [`firmware/README.md`](firmware/README.md).
 
 ## Repo layout
 
 ```
-firmware/   ESP-IDF project for the ESP32-C6
+firmware/   ESP-IDF project (ESP32-C6 devkit/xiao boards, ESP32-S3 ee02)
 server/     FastAPI server: Immich -> crop/dither/pack -> the frame
 docs/       Wiring and architecture notes
 ```