load local bunfig.toml for bun run earlier (for run.bun option)

[RiskyMH]

Alternative to #15596 where it now only impacts bun run for the same cwd dir. This does not effect bunx (even though according to code it should load it), and isnt as fancy as bun install where it ensures to check the bunfig in package.json dir.

This shouldn't have any performance issues because its already loading the file, but now its loading earlier so it can use run.bun option.

Fixes #11445, (as well as fixes #15484, fixes #15483)

[robobun]

^{Updated 11:07 PM PT - Jan 23rd, 2025}

❌ @RiskyMH, your commit 13fe91c has 2 failures in #10441:

• test/regression/issue/09041.test.ts - 1 failing on 🐧 22.04 x64-baseline
• test/js/node/test/parallel/test-http-chunk-problem.js - code 1 on 🐧 3.20 aarch64

---

🧪   try this PR locally:

bunx bun-pr 16664

[pfgithub]

Should add a test that shows what this affects and makes sure it doesn't regress

[RiskyMH]

Should add a test that shows what this affects and makes sure it doesn't regress

Done, I think my 3 cases should be appropriate:

• loads the config on same cwd
• doesn't load it in sub dir, even though its next to package.json
• doesn't load global

The second one could in theory be changed, but I am trying not have any perf change this time (and be minimal changes). bun install is an example of command that does read on same dir.