feat(web): adopt cyberspace terminal aesthetic + dithered images

Rebrand light/dark themes to the cyberspace.online look: warm cream-on-black
palette (light/dark are exact inverses), self-hosted JetBrains Mono + VT323,
square corners, border-driven surfaces with no soft shadows. Adds a terminal
design-system CSS layer (DOS double-border modals with hatched corner, fg focus,
inversion-on-hover), a theme-aware <RasterImage> (Atkinson-dithered canvas with
img fallback), and unifies desktop icons, taskbar, window controls, pills and
links under one idiom. Pins window titlebars to a fixed height and switches chat
auto-scroll off scrollIntoView to avoid titlebar reflow.

VERSION 0.15.1 -> 0.16.0

web/src/lib/components/FleetMap.svelte

@@ -1101,7 +1101,7 @@
     font-size: 12px;
     font-weight: 500;
     border: 1px solid var(--border);
-    border-radius: 999px;
+    border-radius: 0;
     background: transparent;
     color: var(--muted-foreground);
     cursor: pointer;
@@ -1114,9 +1114,12 @@
     border-color: var(--primary);
   }
   .chip.on {
-    color: var(--foreground);
-    background: var(--secondary);
-    border-color: var(--primary);
+    color: var(--background);
+    background: var(--foreground);
+    border-color: var(--foreground);
+  }
+  .chip.on b {
+    color: var(--background);
   }
   .chip .dot {
     width: 8px;