Phase 6: character creation & level-up

- Ability generation: standard array, point buy (27-pt, validated), 4d6kh3 roll;
  AbilityGenModal with assign-from-pool + steppers (pure abilityGen lib + tests)
- Level-up flow: increment level, HP gain (average or roll hit die + CON)
- Print / save-to-PDF: print button + @media print hides app chrome and roll tray
- Plan: added Phase 11 (data-driven Assistant) to the roadmap

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/styles/globals.css

@@ -85,6 +85,21 @@ body {
   scrollbar-color: var(--app-line) transparent;
 }
 
+/* Print: hide app chrome so a character sheet prints (or saves to PDF) cleanly. */
+@media print {
+  header,
+  [data-roll-tray] {
+    display: none !important;
+  }
+  main {
+    overflow: visible !important;
+  }
+  body {
+    background: #fff;
+    color: #000;
+  }
+}
+
 /* Dice roll animations */
 @keyframes dice-tumble {
   0% {