docs(eink): the two e-ink builds in the docs and the site's sim

Docs: the E-ink section describes the landscape and portrait builds, what
the tall screens add, and the settings, with three screenshots; the e-ink
build flags; the release file names. Sim: each orientation gets its own
factory, so a page can load both, and simEinkScale 0 leaves the canvas'
CSS size to the page. CI builds both into solo-sim-wasm.zip (wasm/eink/).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

variants/sim/build_wasm.sh

@@ -200,12 +200,13 @@ fi
 SIM_EINK="${SIM_EINK:-}"
 if [ -n "$SIM_EINK" ]; then
   case "$SIM_EINK" in
-    landscape) EINK_DEFS=(-DDISPLAY_ROTATION=1 -DEINK_LARGE_FONT=1) ;;
-    portrait)  EINK_DEFS=(-DDISPLAY_ROTATION=0) ;;
+    landscape) EINK_DEFS=(-DDISPLAY_ROTATION=1 -DEINK_LARGE_FONT=1); EXPORT_NAME=MeshCoreSimEinkLandscape ;;
+    portrait)  EINK_DEFS=(-DDISPLAY_ROTATION=0);                     EXPORT_NAME=MeshCoreSimEinkPortrait ;;
     *) echo "error: SIM_EINK must be landscape or portrait" >&2; exit 1 ;;
   esac
   OUT_NAME="meshcore_sim_eink_$SIM_EINK"
-  EXPORT_NAME=MeshCoreSimEink   # distinct factory: web/mesh.html?a=... loads it beside MeshCoreSim
+  # Distinct factories (set above): web/mesh.html?a=... loads one beside
+  # MeshCoreSim, and the site loads both orientations into one page.
   kept=()
   for d in "${DEFINES[@]}"; do
     case "$d" in -DDISPLAY_CLASS=*|-DMAX_GROUP_CHANNELS=*) ;; *) kept+=("$d") ;; esac

variants/sim/target.cpp

@@ -174,15 +174,15 @@ SimEinkDisplay::SimEinkDisplay()
 }
 
 // Sizes the page's canvas to the panel as it's turned, at Module.simEinkScale
-// (default 3) CSS pixels a pixel.
+// (default 3) CSS pixels a pixel; 0 leaves the CSS size to the page.
 static void simEinkFitCanvas(int w, int h) {
   EM_ASM({
     var tag = (typeof Module !== 'undefined' && Module['simInstanceTag']) ? Module['simInstanceTag'] : '';
     var c = document.getElementById(tag ? ('sim-canvas-' + tag) : 'sim-canvas');
     if (!c) { console.error('[sim] e-ink canvas not found in the host page'); return; }
-    var k = Module.simEinkScale || 3;
+    var k = ('simEinkScale' in Module) ? Module.simEinkScale : 3;
     c.width = $0; c.height = $1;
-    c.style.width = ($0 * k) + 'px'; c.style.height = ($1 * k) + 'px';
+    if (k) { c.style.width = ($0 * k) + 'px'; c.style.height = ($1 * k) + 'px'; }
     Module.__simCtx = c.getContext('2d');
     Module.__simCtx.imageSmoothingEnabled = false;
     Module.__einkRefreshes = Module.__einkRefreshes || 0;

variants/sim/web/index.html

@@ -215,7 +215,7 @@
       }
     }
 
-    const SimFactory = window.MeshCoreSimEink || window.MeshCoreSim;
+    const SimFactory = window.MeshCoreSimEinkLandscape || window.MeshCoreSimEinkPortrait || window.MeshCoreSim;
     if (typeof SimFactory !== 'function') {
       statusEl.textContent = 'error: build/meshcore_sim.js missing or failed to load -- run variants/sim/build_wasm.sh first.';
     } else {

variants/sim/web/mesh.html

@@ -238,7 +238,7 @@
   </script>
   <script>
     const logEl = document.getElementById('log');
-    const FactoryA = (opts) => (A_BUILD ? MeshCoreSimEink : MeshCoreSim)(opts);
+    const FactoryA = (opts) => (window.MeshCoreSimEinkLandscape || window.MeshCoreSimEinkPortrait || MeshCoreSim)(opts);
     function log(msg) {
       const line = document.createElement('div');
       line.textContent = '[' + new Date().toISOString().substr(11, 12) + '] ' + msg;