Add initial Portuguese (pt) translation agent skill (#62001)

[Jayantparashar10]

Description

This PR creates the Portuguese (pt) translation agent skill file as part of the broader initiative to help AI agents produce consistent translations for Airflow's UI.

Changes

• Creates .github/skills/airflow-translations/locales/pt.md with comprehensive Portuguese translation guidelines
• Adds minimal placeholder .github/skills/airflow-translations/SKILL.md for global terminology rules (to be completed in Define global-level translation agent skills #61985)
• Provides real-world examples extracted from existing airflow-core/src/airflow/ui/public/i18n/locales/pt/*.json files

Content Overview

The pt.md skill file includes:

1. Core Airflow Terminology - Terms that must remain in English (Dag, Asset, Backfill, XCom, etc.)
2. Portuguese-Specific Guidelines - Gender agreement, plural forms, capitalization, spelling conventions
3. Translation Examples - Real patterns from existing JSON files showing correct translations
4. Agent Instructions - Clear DO/DON'T rules for AI translation agents

Testing Strategy

After merge, any AI agent supporting "skills" context can:

1. Load this file as reference material
2. Receive new English UI strings for translation
3. Output Portuguese translations matching existing style/conventions

Example test case:

• Input: "retry_delay": "Retry delay in seconds"
• Expected: "retry_delay": "Atraso de retentativa em segundos"
• Validation: Matches Portuguese style from existing files

Alignment

• Follows the structure established in add SKILL.md and zh-CN agent skill instruction #62059 (zh-CN skill)
• Part of meta-issue Define Translation Agent Skills for Airflow Terminology #61984 for translation agent skills

Closes: #62001

Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)

[boring-cyborg]

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[Jayantparashar10]

Hi @jason810496,

Opened this as a draft PR with the initial pt.md content based on the existing Portuguese JSON files.

Happy to adjust any vocabulary, add/remove examples, or refine the rules based on feedback from Portuguese maintainers.

Thanks again for the assignment and guidance!