docs: fix first-contributor guide typos

[charles-openclaw]

Summary

• Fix the five issue-reported typos in README.md and the first-contributor guides.
• Covers contibution, developpers, responsivness, unfimiliar, and comitting.

Verification

• rg -n 'contibution|developpers|responsivness|unfimiliar|comitting' README.md guides returned no matches.
• git diff --check passed.

Issue reference

Closes #1
Closes #2
Closes #3
Closes #4
Closes #5

Did you follow CONTRIBUTING.md?

• I claimed the issue in a comment before starting
• My commit messages are clear and use the imperative form
• My change does only what the issue asked for -- no unrelated edits

[github-actions]

Hi! This looks like your first pull request to this repo — welcome. 🎉

A maintainer will take a look soon. While you wait:

• Make sure CI is green (the markdown lint check is informational and won't block your merge).
• Feel free to update the PR with more commits if you spot something — we won't squash until merge.
• If we ask for changes, that's normal — every PR, including ones from senior engineers, gets feedback.

Thanks for contributing.