feat(kanban): Seleccionar Aleatorio en columna con ruleta (issue 0090)

Adds a column-level "Seleccionar Aleatorio" context menu entry that picks
a card at random from the column with a roulette-style highlight
animation that decelerates to the winner.

Selection respects existing filters (uses cardsByColumn which is the
post-filter view) and always excludes locked cards. Menu entry is
disabled when nothing pickable is left.

Implementation:
- KanbanColumn: new Menu.Item with IconDice5; data-test selector for e2e.
- onPickRandom prop wired from KanbanColumn -> App.
- handlePickRandom in App.tsx: cryptographically random winner via
  crypto.getRandomValues, 2 full laps + offset, cubic decay 50ms -> 220ms,
  follows the active card with scrollIntoView.
- src/styles/roulette.css: .kanban-roulette-active (blue pulse, single
  step) and .kanban-roulette-winner (green pulse + scale, ~1.6s).
  Imported globally from main.tsx.

Manual verification only (visual timing + needs real cards). Backend
untouched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/App.tsx

@@ -811,6 +811,68 @@ export function App() {
     }
   }, [reload]);
 
+  // Issue 0090: ruleta de seleccion aleatoria por columna.
+  // Recorre las cards visibles (post-filtro) no bloqueadas con highlight
+  // acelerado-decelerado y termina con flash verde sobre la ganadora.
+  const handlePickRandom = useCallback((columnId: string) => {
+    const cards = (cardsByColumn.get(columnId) || []).filter((c) => !c.locked);
+    if (cards.length === 0) {
+      notifications.show({ color: "yellow", message: "No hay cards disponibles (filtro y bloqueadas excluidas)" });
+      return;
+    }
+    if (cards.length === 1) {
+      const el = document.querySelector<HTMLElement>(`[data-card-id="${cards[0].id}"]`);
+      if (el) {
+        el.scrollIntoView({ behavior: "smooth", block: "center" });
+        el.classList.add("kanban-roulette-winner");
+        setTimeout(() => el.classList.remove("kanban-roulette-winner"), 1700);
+      }
+      return;
+    }
+
+    // Decide ganadora con seguridad criptografica.
+    const winnerIdx = (() => {
+      const buf = new Uint32Array(1);
+      crypto.getRandomValues(buf);
+      return buf[0] % cards.length;
+    })();
+
+    // Total steps: minimo 2 vueltas completas + offset hasta la ganadora.
+    const baseLaps = 2;
+    const totalSteps = baseLaps * cards.length + ((winnerIdx - 0 + cards.length) % cards.length);
+
+    // Decay temporal: empieza rapido (50ms), termina lento (220ms).
+    const startMs = 50;
+    const endMs = 220;
+    const easeOut = (t: number) => 1 - Math.pow(1 - t, 3);
+
+    let step = 0;
+    const tick = () => {
+      const idx = step % cards.length;
+      const prevIdx = (idx - 1 + cards.length) % cards.length;
+      const prevEl = document.querySelector<HTMLElement>(`[data-card-id="${cards[prevIdx].id}"]`);
+      const currEl = document.querySelector<HTMLElement>(`[data-card-id="${cards[idx].id}"]`);
+      if (prevEl) prevEl.classList.remove("kanban-roulette-active");
+      if (currEl) {
+        currEl.classList.add("kanban-roulette-active");
+        currEl.scrollIntoView({ behavior: "smooth", block: "center" });
+      }
+      step++;
+      if (step > totalSteps) {
+        if (currEl) {
+          currEl.classList.remove("kanban-roulette-active");
+          currEl.classList.add("kanban-roulette-winner");
+          setTimeout(() => currEl.classList.remove("kanban-roulette-winner"), 1700);
+        }
+        return;
+      }
+      const t = totalSteps > 0 ? step / totalSteps : 1;
+      const delay = startMs + (endMs - startMs) * easeOut(t);
+      setTimeout(tick, delay);
+    };
+    tick();
+  }, [cardsByColumn]);
+
   const handleSetMaxTimeMinutes = useCallback(async (id: string, max_time_minutes: number) => {
     setBoard((prev) => {
       if (!prev) return prev;
@@ -1009,6 +1071,7 @@ export function App() {
                       onDeleteColumn={handleDeleteColumn}
                       onSetWIPLimit={handleSetWIPLimit}
                       onSetMaxTimeMinutes={handleSetMaxTimeMinutes}
+                      onPickRandom={handlePickRandom}
                       onToggleDone={handleToggleDone}
                       onEditCard={openEditCard}
                       onDeleteCard={handleDeleteCard}
@@ -1278,6 +1341,7 @@ export function App() {
                     onDeleteColumn={handleDeleteColumn}
                     onSetWIPLimit={handleSetWIPLimit}
                       onSetMaxTimeMinutes={handleSetMaxTimeMinutes}
+                      onPickRandom={handlePickRandom}
                     onToggleDone={handleToggleDone}
                     onEditCard={openEditCard}
                     onDeleteCard={handleDeleteCard}