feat: bundle code with bun when runtime is bun

[capaj]

Is your feature request related to a problem? Please describe.

I realized trigger.dev still bundles with esbuild when using bun runtime. This can easily create discrepancies when the code is written with bun and tested with bun. For example when using bunfig.toml to define custom loaders-these won't work at all in trigger. One issue I logged earlier is: https://github.com/triggerdotdev/trigger.dev/issues/2657

Describe the solution you'd like to see

Use bun for bundling the code when runtime is bun

Describe alternate solutions

cannot think of any

Additional information

No response