Add ink theme and remove onyx border class

Add an "Ink" theme for e-ink displays and remove the previously applied
onyx-border class from the App container. The new theme defines
high-contrast monochrome variables, suppresses shadows and decorative
effects, adjusts scrollbars and select options, and adds a subtle
linux-window-border color suitable for e-ink screens. The onyx border
CSS was removed and the App.svelte container no longer toggles the
onyx-border class; the Settings screen now includes the Ink option in
the theme selector.
Remove unnecessary blank line in app.css

Remove an unneeded blank line in the Tauri app stylesheet. The extra
line was left behind when considering a mode elimination and is not
required, so this cleans up the CSS file to keep it tidy and consistent.

apps/tauri/src/App.svelte

@@ -14,7 +14,7 @@
 </script>
 
 <div class={app.isDark ? "dark" : ""} data-theme={app.currentTheme ?? ""}>
-  <div class="h-screen w-screen" class:p-2={isLinux} class:onyx-border={app.currentTheme === "onyx"}>
+  <div class="h-screen w-screen" class:p-2={isLinux}>
     <div
       class="relative h-full w-full overflow-hidden bg-surface-light text-text-light dark:bg-surface-dark dark:text-text-dark"
       class:rounded-xl={isLinux}

apps/tauri/src/app.css

@@ -195,10 +195,6 @@ body {
   border-color: rgba(209, 191, 130, 0.15);
 }
 
-/* Thick gold window border */
-[data-theme="onyx"] .onyx-border {
-  border: 3px solid #a6905a;
-}
 
 [data-theme="solarized"] {
   --color-primary: #268bd2;
@@ -216,6 +212,42 @@ body {
   --color-danger: #dc322f;
 }
 
+
+/* ── Ink (e-ink screen) theme ────────────────────────────────────── */
+
+[data-theme="ink"] {
+  --color-primary: #000000;
+  --color-primary-hover: #1a1a1a;
+  --color-surface-light: #ffffff;
+  --color-surface-dark: #ffffff;
+  --color-card-light: #f0f0f0;
+  --color-card-dark: #f0f0f0;
+  --color-text-light: #000000;
+  --color-text-dark: #000000;
+  --color-text-secondary-light: #444444;
+  --color-text-secondary-dark: #444444;
+  --color-border-light: #000000;
+  --color-border-dark: #000000;
+  --color-danger: #000000;
+}
+
+/* Suppress all shadows and decorative effects on ink screens */
+[data-theme="ink"] * {
+  box-shadow: none !important;
+  text-shadow: none !important;
+  scrollbar-color: #444444 transparent;
+}
+[data-theme="ink"] ::-webkit-scrollbar-thumb {
+  background: #444444;
+}
+[data-theme="ink"] select option {
+  background-color: #ffffff;
+  color: #000000;
+}
+[data-theme="ink"] .linux-window-border {
+  border-color: rgba(0, 0, 0, 0.5);
+}
+
 /* ── Accessibility: Reduced motion ───────────────────────────────── */
 
 @media (prefers-reduced-motion: reduce) {

apps/tauri/src/lib/screens/SettingsScreen.svelte

@@ -260,6 +260,7 @@
       <option value="dracula">Dracula</option>
       <option value="solarized">Solarized Dark</option>
       <option value="onyx">Black and Gold</option>
+      <option value="ink">Ink</option>
     </select>
   </section>