feat: add devcontainer config

[Githubguy132010]

Related GitHub Issue

Closes: #8978

Roo Code Task Context (Optional)

(none)

Description

• Adds .devcontainer/devcontainer.json to standardize local development: Ubuntu 24.04 base image, Node.js 20.19.2, pnpm 10.8.1, initialization that pre-creates ${localEnv:HOME}/.pnpm-store, port forwarding, post-create/update install hooks, and recommended VS Code extensions/settings.
• Updates README.md and every localized README to call out “Open in Dev Container” as the recommended first step after cloning, while tidying the collapsible language selector markup.
• Mirrors the Dev Container setup guidance in CONTRIBUTING.md so contributors consistently bootstrap the repo inside the containerized environment.

Test Procedure

1. In VS Code choose Reopen in Container and wait for the dev container build to finish (verifies the new initialize and post-create commands).
2. Inside the container run pnpm install to confirm dependency install succeeds without pnpm cache mount errors.
3. Inside the container run pnpm lint and pnpm test.

Unable to execute pnpm commands in this read-only environment; please run the above steps locally.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Screenshots / Videos

N/A

Documentation Updates

• Yes, documentation updates are required. (Added Dev Container instructions across README translations.)
• No documentation updates are required.

Additional Notes

(none)

---

Important

Adds devcontainer configuration for standardized development and updates documentation to recommend using it as the first step after cloning.

• Devcontainer Configuration:
  • Adds .devcontainer/devcontainer.json for standardized development: Ubuntu 24.04, Node.js 20.19.2, pnpm 10.8.1, pre-creates ${localEnv:HOME}/.pnpm-store, port forwarding, post-create/update install hooks, and recommended VS Code extensions/settings.
• Documentation Updates:
  • Updates README.md to recommend "Open in Dev Container" as the first step after cloning.
  • Mirrors Dev Container setup guidance in CONTRIBUTING.md for consistent contributor onboarding.
• Misc:
  • Tidies collapsible language selector markup in README.md and localized READMEs.

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[roomote]

The .npmrc fix was reverted. The original pnpm cache issue remains unresolved.

• Configure pnpm to use the mounted store directory at /home/vscode/.pnpm-store

Previous Reviews

• 93bc4e4: Review #1
• 70ba784: Review #2

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