Fix oxlint errors: non-null assertions, sort→toSorted, unused vars

- cs-major-simulator.ts: replace 5 non-null assertions (!) with safe
  optional chaining / if-guards; replace 6 .sort() with .toSorted()
- cs2-major-stage.ts: remove unused `inArray` import
- cs2-setup.tsx: remove unused `assignedIds` variable

https://claude.ai/code/session_019w21Nkf5TvTZHH6oVHaQXR

app/models/cs2-major-stage.ts

@@ -14,7 +14,7 @@
 
 import { database } from "~/database/context";
 import { cs2MajorStageResults, participants } from "~/database/schema";
-import { eq, and, inArray, sql } from "drizzle-orm";
+import { eq, and, sql } from "drizzle-orm";
 
 export interface Cs2StageResult {
   id: string;

app/routes/admin.sports-seasons.$id.events.$eventId.cs2-setup.tsx

@@ -119,9 +119,6 @@ export default function AdminCs2Setup() {
   const navigation = useNavigation();
   const isSubmitting = navigation.state === 'submitting';
 
-  // Build maps from existing stage results
-  const assignedIds = new Set(stageResults.map(r => r.participantId));
-
   // Stage assignment state (local, submitted via form)
   const [stageSelections, setStageSelections] = useState<Record<string, string>>(() => {
     const initial: Record<string, string> = {};

app/services/simulations/cs-major-simulator.ts

@@ -120,7 +120,7 @@ export function sampleField(
   pool: TeamWithElo[],
   fieldSize: number = FIELD_SIZE
 ): TeamWithElo[] {
-  const sorted = [...pool].sort((a, b) => a.rank - b.rank);
+  const sorted = [...pool].toSorted((a, b) => a.rank - b.rank);
 
   if (sorted.length <= fieldSize) return sorted;
 
@@ -146,8 +146,8 @@ function weightedSampleWithoutReplacement<T>(
 ): T[] {
   const keys = weights.map((w) => -Math.log(Math.random()) / w);
   const indexed = items.map((item, i) => ({ item, key: keys[i] }));
-  indexed.sort((a, b) => a.key - b.key);
-  return indexed.slice(0, count).map((x) => x.item);
+  const sortedIndexed = indexed.toSorted((a, b) => a.key - b.key);
+  return sortedIndexed.slice(0, count).map((x) => x.item);
 }
 
 // ─── Swiss stage simulation ───────────────────────────────────────────────────
@@ -213,13 +213,13 @@ export function simulateSwiss(teams: TeamWithElo[], bo3: boolean): SwissResult {
 
       if ((wins.get(winnerId) ?? 0) >= 3) {
         advancedIds.add(winnerId);
-        const t = teamById.get(winnerId)!;
-        advanced.push({ id: t.id, elo: t.elo, rank: t.rank });
+        const t = teamById.get(winnerId);
+        if (t) advanced.push({ id: t.id, elo: t.elo, rank: t.rank });
       }
       if ((losses.get(loserId) ?? 0) >= 3) {
         eliminatedIds.add(loserId);
-        const t = teamById.get(loserId)!;
-        eliminated.push({ id: t.id, elo: t.elo, rank: t.rank, wins: wins.get(loserId) ?? 0 });
+        const t = teamById.get(loserId);
+        if (t) eliminated.push({ id: t.id, elo: t.elo, rank: t.rank, wins: wins.get(loserId) ?? 0 });
       }
     }
   }
@@ -237,7 +237,7 @@ function groupByRecord(
   for (const t of active) {
     const key = `${wins.get(t.id) ?? 0}-${losses.get(t.id) ?? 0}`;
     if (!groups.has(key)) groups.set(key, []);
-    groups.get(key)!.push(t);
+    groups.get(key)?.push(t);
   }
   return groups;
 }
@@ -287,7 +287,7 @@ export function simulateChampionsStage(teams: TeamWithElo[]): ChampionsResult {
   }
 
   // Seed by rank ascending
-  const seeded = [...teams].sort((a, b) => a.rank - b.rank);
+  const seeded = [...teams].toSorted((a, b) => a.rank - b.rank);
   // Standard 8-team seeding: 1v8, 4v5, 3v6, 2v7
   const bracket: [TeamWithElo, TeamWithElo][] = [
     [seeded[0], seeded[7]],
@@ -353,12 +353,12 @@ function calcStage3ExitQP(
   const byWins = new Map<number, string[]>();
   for (const t of elimTeams) {
     if (!byWins.has(t.wins)) byWins.set(t.wins, []);
-    byWins.get(t.wins)!.push(t.id);
+    byWins.get(t.wins)?.push(t.id);
   }
 
   // Assign placement slots 9–16 from highest wins first
   const result = new Map<string, number>();
-  const winsGroups = [...byWins.entries()].sort((a, b) => b[0] - a[0]);  // descending wins
+  const winsGroups = [...byWins.entries()].toSorted((a, b) => b[0] - a[0]);  // descending wins
 
   let slotStart = 9;
   for (const [, ids] of winsGroups) {
@@ -415,10 +415,10 @@ export class CSMajorSimulator implements Simulator {
     const pool: TeamWithElo[] = participantIds
       .filter((id) => eloMap.has(id))
       .map((id) => {
-        const e = eloMap.get(id)!;
-        return { id, elo: e.elo, rank: e.rank };
+        const e = eloMap.get(id);
+        return { id, elo: e?.elo ?? FALLBACK_ELO, rank: e?.rank ?? 9999 };
       })
-      .sort((a, b) => a.rank - b.rank);
+      .toSorted((a, b) => a.rank - b.rank);
 
     if (pool.length === 0) {
       throw new Error(
@@ -497,7 +497,7 @@ export class CSMajorSimulator implements Simulator {
       }
 
       // Rank all participants by total QP descending.
-      const ranked = [...simQP.entries()].sort((a, b) => b[1] - a[1]);
+      const ranked = [...simQP.entries()].toSorted((a, b) => b[1] - a[1]);
       for (let rank = 0; rank < Math.min(8, ranked.length); rank++) {
         const [pid] = ranked[rank];
         const idx = idToIndex.get(pid);
@@ -564,7 +564,7 @@ function simulateOneMajor(
     stage3Direct = s3;
   } else {
     const field = sampleField(pool, FIELD_SIZE);
-    const sorted = [...field].sort((a, b) => a.rank - b.rank);
+    const sorted = field.toSorted((a, b) => a.rank - b.rank);
     stage3Direct = sorted.slice(0, 8);
     stage2Direct = sorted.slice(8, 16);
     stage1Teams  = sorted.slice(16, 32);