e2e-codex-launch-test: add HELLO.md

[proboscis]

Summary

• Added HELLO.md in repository root with exact required content: Hello from codex

Acceptance Criteria Evidence

Issue: e2e-codex-launch-test

1. Create HELLO.md with text "Hello from codex"

Command run:

ls -l HELLO.md
sed -n '1,20p' HELLO.md

Observed output:

-rw-r--r--@ 1 s22625  1796141739  17 Feb 12 13:53 HELLO.md
Hello from codex

Validation

Ran:

go test ./...

Result:

• Most packages passed.
• One existing failure in internal/cli:
  • TestApplyConfigDefaultsFallbacks (run_test.go:344) reported invalid config schema ... EOF.