chore(docs): scaffold translations for Hacktoberfest

[AAYUSH-SPIDEY-SHARMA]

Adds translations scaffold to make docs translatable and invite community contributions.
What is included:

• docs/en/ (canonical English docs copied from README)
• TRANSLATIONS.md (translation workflow & rules)
• CONTRIBUTING.md: added Translating docs section
• .github/PULL_REQUEST_TEMPLATE.md (translation checklist)
• .github/scripts/auto_translate.py (helper to generate machine-draft translations locally)
• .github/workflows/translate.yml (optional workflow to create auto-PRs)

Notes & requests for maintainers:

• This is scaffold-only. No machine-translated docs are included in this PR.
• Please review the workflow script (auto_translate.py) before enabling it in CI — it uses deep-translator (not an official API) and is intended for drafts only.
• I will create small translation issues (good-first-issue) once this is merged.

Security: no secrets or service-account files are included. Do not commit secrets to the repo.

closes #15