fix(kms): consider all connected connectors when picking primary gpu

[techywilbur]

determine_primary_gpu looked for a built-in laptop panel (eDP/LVDS/DSI) by scanning only connectors that already had a Surface (dev.inner.surfaces.values()). At startup a connector may not have been turned into a Surface yet, or its Surface creation may have transiently failed, so the internal panel could be missed and the wrong render GPU selected on a hybrid (e.g. Intel + NVIDIA) laptop when an external display is connected at boot.

Instead, enumerate every connector via resource_handles() and treat a device as holding the built-in panel only when an internal-interface connector reports ConnectorState::Connected. A device that fails to report resource handles is skipped rather than aborting selection for all devices. Preserves the existing COSMIC_RENDER_DEVICE, boot-gpu and first-device fallbacks unchanged.

Adds trace/info logging of which connectors were considered and why a GPU was chosen, plus a unit test for the internal-panel predicate.

This mirrors the approach of the upstream branch
fix-check-all-connectors_noble (9c95ebf, Victoria Brekenfeld); it is a candidate for pop-os/cosmic-comp issue #3751 and does not claim to resolve every report in that issue (a single-GPU report is unlikely to be affected by primary-gpu selection).

• I have disclosed use of any AI generated code in my commit messages.
  • If you are using an LLM, and do not fully understand the changes it is making to the code base, do not create a PR.
  • In our experience, AI generated code often results in overly complex code that lacks enough context for a proper fix or feature inclusion. This results in considerably longer code reviews. Due to this, AI authored or partially authored PRs may be closed without comment.
• I understand these changes in full and will be able to respond to review comments.
• My change is accurately described in the commit message.
• My contribution is tested and working as described.
• I have read the Developer Certificate of Origin and certify my contribution under its conditions.

[Drakulix]

See

#2621
and #2624