feat(i18n): add European Portuguese localization

[roxi3906]

Problem

Open Science ships translated interface locales, but users in Portugal cannot select a fully localized European Portuguese experience. Locale detection, native main-process messages, date formatting, release metadata, and persisted language selection did not recognize pt-PT.

Proposed change

• Add a complete pt-PT catalog and register it across shared, main, renderer, update-manifest, and CI ownership boundaries.
• Add explicit European Portuguese BCP-47 detection while rejecting bare pt, pt-BR, other Portuguese regions, and private-use lookalikes.
• Add Português (Portugal) selection, native quit-dialog copy, locale-aware formatting, and restart persistence at narrow desktop widths.
• Refresh the existing Draft PR through upstream/main@f37896a8 with normal merge commits and no history rewriting; every merge completed without textual conflicts.
• Translate 16 user-visible keys introduced by the merged main updates directly from English into European Portuguese, including the latest CodeBuddy framework description, requirement hint, and app-runtime download explanation.
• Preserve the technical distinction between the app-managed installation runtime and the app runtime that executes CodeBuddy.
• Verify the latest expanded Skill-document preview reuses the reviewed European Portuguese copy: Competência, Tentar novamente, and A carregar pré-visualização…; the loaded SKILL.md remains exact technical content.
• Enforce reviewed Portugal terminology, sentence case, exact technical identifiers, progress grammar, and one / many / other plural categories.
• Add exact semantic guards plus scans for Brazilian vocabulary and malformed mechanical replacements.
• Add a European Portuguese README and update localization contribution, glossary, release-note, and navigation documentation.

Scope and non-goals

• No runtime translation service, new dependency, or dynamic catalog inheritance.
• No mapping of generic or Brazilian Portuguese tags to European Portuguese.
• No redesign of the language picker or settings UI.
• Existing locales continue to fall back directly to English.

Acceptance criteria and validation

• npx vitest run src/renderer/src/i18n/resources.test.ts: 874 passed, including exact contracts for all three CodeBuddy strings.
• CodeBuddy/settings/CI integration slice: 1,256 passed before the no-locale catch-up merges.
• Exact-final-increment slices: 1,060 passed after main@960a54e4; 1,055 passed after main@07a8f5ca.
• Latest-main slices: 906 passed after the Web-service merge and 933 passed after the expanded Skill-document preview merge.
• npx playwright test e2e/settings-persistence.spec.ts: 12 passed, including pt-PT native quit copy, 640 px fit, and restart persistence.
• npm run typecheck: passed on final local head 99b9594d.
• npm run build and npm run build:e2e: passed locally for the CodeBuddy translation merge; the exact final head also passed macOS build/E2E and Windows E2E in PR Gate.
• npm run lint: 0 errors; 256 formatting warnings already present in merged main test files.
• Full local npm test: 20,377 passed and 232 skipped; two unrelated failures were reproduced unchanged on exact upstream/main@da4dadc7 (Claude ACP dependency behavior and the system Python version used by the literature-review kernel).
• Independent Standards and European Portuguese Spec reviews: one runtime-distinction wording issue fixed in 32b7af9c; final re-review found no remaining actionable issues.
• Exact-head GitHub checks for 99b9594d are green: CI Integrity, Static checks, both full Module-test shards, coverage aggregation, Windows core/E2E, macOS build/E2E, and the aggregate PR Gate all passed.

Review focus

• Native European Portuguese wording for safety-sensitive actions, Marketplace, Specialist, session, credential, preview, CodeBuddy, and technical configuration surfaces.
• Exact preservation of placeholders, Trans tags, paths, commands, product names, and fields such as User, Port, Node.js, and npm.
• Region-position parsing for pt-PT, pt-Latn-PT, pt-PT-x-*, and rejection of other Portuguese regions/private-use tags.
• Main-process ownership, release metadata, CI classification, narrow-layout fit, and restart persistence.