fix(types): repair typecheck after oxlint safe autofix

The safe --fix introduced three type issues:

1. unicorn/prefer-set-has rewrote array literals to `new Set(...)`
   without updating the `T[]` type annotation — broken assignment.
   Fix type to `Set<T>` in logger.ts and agent-manager.ts.

2. unicorn/no-array-reverse changed `.reverse()` → `.toReversed()`
   (ES2023). Bump `lib` to ES2023 in tsconfig.base.json and
   tsconfig.server.json. Target stays at ES2020 — Node 20 supports
   the methods natively, no downlevel needed.

3. preserve-caught-error added `new Error(msg, { cause })` (ES2022),
   also covered by the lib bump.

packages/server/src/server/agent/agent-manager.ts

@@ -278,7 +278,7 @@ type SubscriptionRecord = {
   agentId: string | null;
 };
 
-const BUSY_STATUSES: AgentLifecycleStatus[] = new Set(["initializing", "running"]);
+const BUSY_STATUSES: Set<AgentLifecycleStatus> = new Set(["initializing", "running"]);
 const AgentIdSchema = z.string().uuid();
 
 function isAgentBusy(status: AgentLifecycleStatus): boolean {

packages/server/src/server/logger.ts

@@ -37,7 +37,7 @@ type ResolveLogConfigOptions = {
   env?: NodeJS.ProcessEnv;
 };
 
-const LOG_LEVELS: LogLevel[] = new Set(["trace", "debug", "info", "warn", "error", "fatal"]);
+const LOG_LEVELS: Set<LogLevel> = new Set(["trace", "debug", "info", "warn", "error", "fatal"]);
 const LOG_FORMATS: LogFormat[] = ["pretty", "json"];
 const LOG_LEVEL_PRIORITIES: Record<LogLevel, number> = {
   trace: 10,