feat(linux/pipewire): Add support for pipewire stream selection by object serial

[Kishi85]

Description

Add support for selecting pipewire stream via object serial in addition to current selection via node id.
Selecting via node id has known re-use issues and is therefore deprecated by pipewire. When a valid object serial is specified (lower bits != SPA_ID_INVALID) it will be preferred over node id. Since object serial is currently not set by portalgrab the current behaviour will therefore be unchanged.

This is to lay the groundwork for upcoming recommended changes in XDG portal (and also recommended to use with kde-screencast-v2/newer zkde_screencast_unstable_v1 iterations once available).

This PR will also fix the type of the node id parameter to match pipewire's uint32_t.

Screenshot

Issues Fixed or Closed

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

• 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

[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

[codecov]

Codecov Report

❌ Patch coverage is 0% with 12 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (master@1fc88f8). Learn more about missing BASE report.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/platform/linux/pipewire.cpp	0.00%	10 Missing and 1 partial ⚠️
src/platform/linux/portalgrab.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5054   +/-   ##
=========================================
  Coverage          ?   18.17%           
=========================================
  Files             ?      109           
  Lines             ?    23570           
  Branches          ?    10398           
=========================================
  Hits              ?     4285           
  Misses            ?    14897           
  Partials          ?     4388           

Flag	Coverage Δ
Archlinux	11.53% <0.00%> (?)
FreeBSD-14.3-amd64	13.77% <0.00%> (?)
Homebrew-ubuntu-22.04	13.90% <0.00%> (?)
Linux-AppImage	12.49% <0.00%> (?)
Windows-AMD64	14.86% <ø> (?)
Windows-ARM64	13.23% <ø> (?)
macOS-arm64	19.07% <ø> (?)
macOS-x86_64	18.42% <ø> (?)

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

Files with missing lines	Coverage Δ
src/platform/linux/portalgrab.cpp	18.57% <0.00%> (ø)
src/platform/linux/pipewire.cpp	0.00% <0.00%> (ø)

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1fc88f8...5acbfc6. Read the comment docs.

[codecov]

Bundle Report

Bundle size has no change ✅