fix: avoid hard-coded repo path in conda onboarding guide

[cursor]

Summary

• replace the hard-coded ~/repos/docs example in tools/conda-nodejs.mdx with a generic repo path placeholder
• clarify that mint dev must run from the cloned docs repository root where docs.json lives

Why

The newly added conda onboarding guide told users to run cd ~/repos/docs before mint dev. Anyone who cloned the docs repo anywhere else would hit cd: no such file or directory, then run mint dev outside the repository and fail to start a local preview. This is a concrete setup-blocking regression in the onboarding flow.

Validation

• reviewed the PR diff against the surrounding Mintlify development docs
• confirmed repo-wide guidance says to run mint dev from the docs directory rather than a fixed filesystem path
• ran git diff --check to verify the patch is clean