feat(sysmon): add a gpu_vram_used stat

[etrobert]

Summary

Add a gpu_vram_used stat.

Motivation

Allows to see VRAM usage in absolute number, mirroring RAM stat.

Type of Change

• Bug fix
• New feature
• Breaking change
• Refactoring
• Build / packaging

Related Issue

No related issue.

Testing

• clang-format --dry-run -Werror over src with v22.1.8: clean.
• Built from source: clean, no new warnings.
• noctalia config validate on a config using both gpu_vram_used and gpu_vram: valid, no warnings. The same config on an unpatched build warns"gpu_vram_used" is not one of the allowed values.
• Did not run the meson test suite; no test references SysmonStat.

Manual Coverage

• Tested on Niri
• Tested on Hyprland
• Tested on Sway
• Tested on another compositor:
• Tested with different bar positions and density settings
• Tested at different interface scaling values
• Tested with multiple monitors

Screenshots / Videos

Closeup as used in my config:

with the following settings:

[widget.vram]
type = "sysmon"
stat = "gpu_vram_used"
glyph = "device-desktop"
label_show_units = false

Checklist

• This PR is ready for review, or it is marked as Draft.
• I read and followed the relevant guidance in CONTRIBUTING.md.
• I ran just format with clang-format v22+ installed, or this PR has no code changes.
• I ran the relevant build or test commands, or explained why they were not run.
• I self-reviewed the changes.
• I checked for new warnings or errors.
• I will update end-user documentation after merge, or this PR does not change user-facing configuration or behavior.
• I added or updated assets/translations/en.json, or this PR adds no new user-facing strings.
• I did not edit non-English translation files unless this PR is explicitly for translation tooling, an import/export sync, or a maintainer-requested locale change.
• I used the existing canonical names for config keys, IPC names, paths, and identifiers.

Additional Notes

RAM has ram_used and ram_pct. To mirror that without renaming existing gpu-vram, named it gpu-vram-used.

VRAM usage in the control center is already displayed in absolute number, now there is a matching option.

Development was assisted by AI.

[ItsLemmy]

Thanks