Open-source restructure v1.1

[WhiteMuush]

Summary

• Foundation: .editorconfig, updated .gitignore (allow docs/, ignore CLAUDE.md)
• Bug fix: Translated 3 remaining French strings to English in the toolkit manager
• CI: GitHub Actions workflow with ShellCheck, bash -n syntax check, and source-chain smoke test
• Templates: Issue templates (bug report, feature request), PR template
• Community: CONTRIBUTING.md, CODE_OF_CONDUCT.md, SECURITY.md
• Documentation: docs/ARCHITECTURE.md (design overview), docs/ADDING_A_TOOL.md (contributor guide)
• README: Added badges (License, CI, PRs Welcome), project layout section, corrected CLI docs

No structural changes to the codebase. All existing functionality preserved.

Test plan

• CI passes (ShellCheck + syntax + smoke test)
• sudo ./bull.sh launches interactive menu
• sudo ./bull.sh help displays CLI help
• Toolkit manager prompts are in English