v1.1.0: Add cancelled course, duplicate prevention, and credit bar ticks

- Mark "Managing Growing Companies" as cancelled with visual indicator and solver exclusion
- Prevent selecting duplicate courses across elective sets (e.g., same course in Spring and Summer)
- Add 2.5-credit interval tick marks to specialization progress bars
- Bump version to 1.1.0 with date display in UI header

app/src/components/SpecializationRanking.tsx

@@ -33,6 +33,12 @@ function CreditBar({ allocated, potential, threshold }: { allocated: number; pot
   const allocPct = Math.min((allocated / maxWidth) * 100, 100);
   const potentialPct = Math.min((potential / maxWidth) * 100, 100);
 
+  // Generate tick marks at 2.5 credit intervals
+  const ticks: number[] = [];
+  for (let t = 2.5; t < maxWidth; t += 2.5) {
+    ticks.push(t);
+  }
+
   return (
     <div style={{ position: 'relative', height: '6px', background: '#e5e7eb', borderRadius: '3px', marginTop: '4px' }}>
       {potential > allocated && (
@@ -51,11 +57,22 @@ function CreditBar({ allocated, potential, threshold }: { allocated: number; pot
           borderRadius: '3px', transition: 'width 300ms ease-out',
         }}
       />
+      {/* Tick marks at 2.5 credit intervals — rendered above bar fills */}
+      {ticks.map((t) => (
+        <div
+          key={t}
+          style={{
+            position: 'absolute', left: `${(t / maxWidth) * 100}%`, top: 0,
+            width: '1px', height: '6px', background: 'rgba(0,0,0,0.2)',
+            zIndex: 1, transition: 'left 300ms ease-out',
+          }}
+        />
+      ))}
       <div
         style={{
           position: 'absolute', left: `${(threshold / maxWidth) * 100}%`, top: '-2px',
           width: '2px', height: '10px', background: '#666',
-          transition: 'left 300ms ease-out',
+          zIndex: 2, transition: 'left 300ms ease-out',
         }}
       />
     </div>