Enforce Dupes Clause and Shiny Clause rules

Dupes Clause greys out Pokemon in the encounter modal whose evolution
family has already been caught, preventing duplicate selections. Shiny
Clause adds a dedicated Shiny Box and lets shiny catches bypass the
one-per-route lock via a new is_shiny column on encounters and a
/pokemon/families endpoint that computes evolution family groups.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/ShinyBox.tsx

@@ -0,0 +1,36 @@
+import { PokemonCard } from './PokemonCard'
+import type { EncounterDetail } from '../types'
+
+interface ShinyBoxProps {
+  encounters: EncounterDetail[]
+  onEncounterClick?: (encounter: EncounterDetail) => void
+}
+
+export function ShinyBox({ encounters, onEncounterClick }: ShinyBoxProps) {
+  return (
+    <div className="border-2 border-yellow-400 dark:border-yellow-600 rounded-lg p-4">
+      <h3 className="text-sm font-semibold text-yellow-600 dark:text-yellow-400 mb-3 flex items-center gap-1.5">
+        <span>&#10022;</span>
+        Shiny Box
+        <span className="text-xs font-normal text-gray-400 dark:text-gray-500 ml-1">
+          {encounters.length} {encounters.length === 1 ? 'shiny' : 'shinies'}
+        </span>
+      </h3>
+      {encounters.length > 0 ? (
+        <div className="grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-2">
+          {encounters.map((enc) => (
+            <PokemonCard
+              key={enc.id}
+              encounter={enc}
+              onClick={onEncounterClick ? () => onEncounterClick(enc) : undefined}
+            />
+          ))}
+        </div>
+      ) : (
+        <p className="text-sm text-gray-400 dark:text-gray-500 text-center py-2">
+          No shinies found yet
+        </p>
+      )}
+    </div>
+  )
+}