Nebula: fatten mobile streamers (undo aspect-squish), fade out the cursor

- Streamers were rendering and hitting the monitor but invisible on phones:
  preserveAspectRatio=none squishes the stroke horizontally on a narrow viewport,
  so 0.12 went sub-pixel. Fatten 2.5x on mobile so they actually show.
- Terminal cursor now types 'such', backspaces, blinks ~6 times, then fades out
  completely instead of blinking forever (it was distracting).

apps/web/src/app/globals.css

@@ -245,13 +245,19 @@
   overflow: hidden;
   width: 0;
   border-right: 1.5px solid currentColor;
-  animation: nebula-type 5s steps(4, end) forwards, nebula-caret 0.9s steps(1, end) infinite;
+  /* type "such", hold, backspace (nebula-type, once); blink a finite number of times
+     (nebula-caret); then fade the whole thing out so it stops being distracting. */
+  animation:
+    nebula-type 3s steps(4, end) forwards,
+    nebula-caret 0.8s steps(1, end) 10,
+    nebula-term-out 0.6s ease-in 7.4s forwards;
 }
 @keyframes nebula-type {
   0% { width: 0; }
-  16% { width: 4ch; }
-  60% { width: 4ch; }
-  74% { width: 0; }
+  27% { width: 4ch; }
+  67% { width: 4ch; }
+  87% { width: 0; }
   100% { width: 0; }
 }
-@keyframes nebula-caret { 50% { border-color: transparent; } }
+@keyframes nebula-caret { 0%, 50% { border-color: currentColor; } 50.01%, 100% { border-color: transparent; } }
+@keyframes nebula-term-out { to { opacity: 0; } }