feat(macOS): add UTF-8 keyboard text input

[ReenigneArcher]

Description

Implement KeyboardTextEvent handling in the macOS backend by converting UTF-8 text to UTF-16 and posting Unicode key-down/key-up CoreGraphics events with current modifier flags. Update platform support docs to mark keyboard text input as supported, and expand macOS backend tests/fixtures to cover successful text input, empty input, invalid UTF-8 rejection, and behavior after device close.

Screenshot

Issues Fixed or Closed

• Closes feat(macos): implement Unicode text input Sunshine#4980

Roadmap Issues

Type of Change

• feat: New feature (non-breaking change which adds functionality)
• fix: Bug fix (non-breaking change which fixes an issue)
• docs: Documentation only changes
• style: Changes that do not affect the meaning of the code (white-space, formatting, missing semicolons, etc.)
• refactor: Code change that neither fixes a bug nor adds a feature
• perf: Code change that improves performance
• test: Adding missing tests or correcting existing tests
• build: Changes that affect the build system or external dependencies
• ci: Changes to CI configuration files and scripts
• chore: Other changes that don't modify src or test files
• revert: Reverts a previous commit
• BREAKING CHANGE: Introduces a breaking change (can be combined with any type above)

Checklist

• Code follows the style guidelines of this project
• Code has been self-reviewed
• Code has been commented, particularly in hard-to-understand areas
• Code docstring/documentation-blocks for new or existing methods/components have been added or updated
• Unit tests have been added or updated for any new or modified functionality

AI Usage

See our AI usage policy.

• None: No AI tools were used in creating this PR
• Light: AI provided minor assistance (formatting, simple suggestions)
• Moderate: AI helped with code generation or debugging specific parts
• Heavy: AI generated most or all of the code changes

[codecov]

Codecov Report

❌ Patch coverage is 24.13793% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.33%. Comparing base (15a37d3) to head (f814c43).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/platform/macos/macos_backend.cpp	24.13%	4 Missing and 18 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #98      +/-   ##
==========================================
- Coverage   75.47%   75.33%   -0.14%     
==========================================
  Files          34       34              
  Lines        8133     8161      +28     
  Branches     3044     3066      +22     
==========================================
+ Hits         6138     6148      +10     
- Misses       1454     1718     +264     
+ Partials      541      295     -246     

Flag	Coverage Δ
FreeBSD	51.72% <ø> (ø)
Linux-Clang	57.48% <ø> (ø)
Linux-GCC	68.19% <ø> (ø)
Windows-MSVC	88.42% <ø> (ø)
Windows-MinGW-UCRT64	65.17% <ø> (ø)
macOS	51.31% <24.13%> (-0.12%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/platform/macos/macos_backend.cpp	41.23% <24.13%> (-0.59%)	⬇️

... and 12 files with indirect coverage changes

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[ReenigneArcher]

@mkrusen could I request that you give this a test with Sunshine? I'm only asking as I don't have any macOS device to test on.

[ReenigneArcher]

I can't test this as I have no macOS device, but going to assume it works. If not feel free to file a bug report.