[WIP] Add Portuguese localisation for all markdown files

[Copilot]

• Create localisation/pt-br directory structure
• Translate main README.md
• Translate product-requirements.md
• Translate docs/README.md
• Translate docs/00-setup.md
• Translate docs/01-python.md
• Translate docs/02-javascript.md
• Translate docs/03-java.md
• Translate docs/04-dotnet.md
• Translate docs/05-containerization.md
• Translate docs/custom-instructions/ files (setup, python, javascript, java, dotnet, containerization)
• Translate complete/README.md
• Translate complete/javascript/README.md
• Translate complete/dotnet/README.md
• Translate complete/python/README.md and complete/java/socialapp/README.md (large files)
• Translate language-specific README files (python/README.md, javascript/README.md, java/README.md, dotnet/README.md)
• Verify all links work correctly and images point to original locations
• Test that the language navigation works properly

Fixes #30.

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[justinyoo]

@copilot It stopped working due to the rate limit. Please continue. When you resume, follow the instructions below:

• Carefully re-examine what you have done for the localisation.
• Make sure that the link in the localised documents should not be broken.
• Make sure that the image links are pointing to the original ones.
• Make sure that all the sections in each doc are localised.
• Make sure that all the prompts in each doc are localised.
• DO NOT add new contents that don't exist in the original doc.
• DO NOT twist the original content from the original doc.
• DO NOT remove the existing content from the original doc.

[Copilot]

@copilot It stopped working due to the rate limit. Please continue. When you resume, follow the instructions below:

• Carefully re-examine what you have done for the localisation.
  ...

Resumed and completed the Portuguese localization as requested. I have:

✅ Reviewed existing localizations and verified they follow all guidelines
✅ Completed missing translations for all remaining README files
✅ Verified all links work correctly - all relative paths preserved
✅ Confirmed image links point to original locations (../../images/, ./images/)
✅ Ensured all sections and prompts are localized while maintaining technical accuracy
✅ Preserved original content structure without additions or modifications

Commit: 3ac2cb3

[justinyoo]

LGTM