Add selection-aware Auto Adjust shortcut

[xcv58]

Description

Adds a canonical, selection-aware Auto Adjust action with a configurable Cmd/Ctrl+U shortcut. The toolbar button, thumbnail context menu, and keyboard shortcut now share the same action path.

Type of Change

• Bug fix
• New feature
• Breaking change
• Performance improvement
• Code refactoring
• Documentation update
• UI/UX improvement
• Build/CI or Dependency update

Changes Made

• Adds the apply_auto_adjustments keybind, defaulting to Cmd/Ctrl+U.
• Applies Auto Adjust to the current photo or the active multi-selection.
• Uses the loaded editor command for the ready current photo and the batch backend for remaining targets.
• Requests confirmation for selections of 10 or more photos, or multi-selections containing existing edits.
• Reuses the canonical action from the toolbar, context menu, and keyboard shortcut.
• Adds localized labels and confirmation copy for all 13 supported locales.
• Adds pure helpers for target resolution and confirmation decisions.

Testing

• These changes were tested locally by a human and confirmed to work.
• I haven't added any automated tests to the code because the codebase currently lacks a test suite.

Test Configuration:

• OS: macOS
• Checks: npm run build, focused helper assertions, locale-key coverage, Prettier, and git diff --check

Checklist

• My code follows the project's code style
• I haven't added unnecessary AI-generated code comments
• My changes generate no new warnings or errors

Additional Notes

The repository-wide TypeScript and i18n validation commands still report pre-existing baseline failures unrelated to this change. This branch is independent from the Settings search PR.

AI Disclaimer

• This PR is created by an AI agent
• This PR is mostly AI-generated but edited/merged together by a human
• This PR was handwritten with AI assistance (spell check, logic suggestions, error resolving)
• This PR contains only blood, sweat, and coffee (AI-free)