Closes #484

Problem

Starting a background task forks a daemon that imports the task file. Three problems made failures opaque and unsafe, reproduced against the real build on Node 24:

1. Real load error hidden. A failed import (missing file; a runtime that cannot run the file; or unsupported TypeScript syntax in Node's strip-only mode, e.g. enum/namespace/decorators) crashed the daemon. The parent only saw Start operation timed out or node-cron daemon exited with code 1; the actual cause (TypeScript enum is not supported in strip-only mode, Cannot find module ...) only reached the child's stderr. This matches @rudewalt (Node 24) and @merencia's loader hypothesis.
2. Hard-coded 5s start timeout. A task file that loads slowly (transpile, large dependency graph) could not be accommodated. This matches the OP and @jsa4000.
3. Orphaned daemons. On a failed/timed-out start the daemon was never killed, so a daemon that finished loading after the timeout kept running the schedule on its own. With retries/nodemon this produced "so many task been executed" (@jsa4000).

Fix

• The daemon catches load/start failures and forwards the real error to the parent (daemon:error); start() rejects with the actual cause.
• New startTimeout option (ms, default 5000) and an actionable timeout message.
• Any failed start now kills the daemon and clears the fork (no orphans/duplicates).
• schedule() routes a background task's auto-start failure to the configured logger instead of leaving an unhandled rejection (the OP's UnhandledRejection).

Tests

Deterministic, written first (red), then made green:

• daemon forwards the real load error instead of crashing;
• parent rejects start() with the real cause on daemon:error;
• parent kills the daemon and clears the fork on a failed start, and on a timeout (no orphan);
• startTimeout is honoured and the timeout message is actionable;
• schedule() logs a background start failure instead of throwing unhandled.

End-to-end verified against the built dist (enum .ts -> real error surfaced; slow load + short startTimeout -> daemon killed, no orphan executions).

Honest scope note

node-cron cannot transpile TypeScript for you: on a strip-only runtime an enum still will not run. This change makes the failure diagnosable (you see the exact reason and how to fix it: --experimental-transform-types, tsx/ts-node, or a compiled .js) and stops the orphaned executions. It does not magically run unsupported syntax.