[Tech Debt] Fix misleading/stale comments across multiple files

[sonikro]

Problem

Several comments are incorrect or stale:

1. PendingServerCleanupRoutine.ts:6 — Wrong schedule comment

// Schedule a job to run every 10 minutes
schedule.scheduleJob('*/15 * * * *', ...);  // Actually every 15 minutes!

2. TerminatePendingServers.ts:66 — Stale Node.js polyfill comment

// Use a local AggregateError polyfill (for Node <15)
const error = new Error(`...`);
(error as any).errors = ...;

The project requires and runs on Node 24. AggregateError is natively available. The comment is misleading, and the code should use native AggregateError.

3. TerminatePendingServers.ts:67 — Log message says wrong threshold

eventMessage: `Server ${server.serverId} terminated after being stuck in pending for over 10 minutes.`

But the actual threshold check is:

if (pendingDuration >= 15 * 60 * 1000) { // 15 minutes

4. DefaultTaskDefinitionService.ts:89 — Stale TODO

// TODO: Remove logging to reduce cost

No owner, no ticket, no context. Either act on it or remove it.

Fix

1. Fix comment in PendingServerCleanupRoutine.ts from "every 10 minutes" to "every 15 minutes"
2. Remove the Node <15 polyfill comment from TerminatePendingServers.ts; use native AggregateError
3. Fix the log message in TerminatePendingServers.ts to say "15 minutes" instead of "10 minutes"
4. Remove the stale TODO comment from DefaultTaskDefinitionService.ts