fix(overlay): prevent GPUI from exiting on window close

[clifinger]

Summary

On Linux, GPUI closes the application when the last window is closed by default. This causes the openlogi-overlay process to exit every time the Actions Ring is dismissed, leading to a long GPU reinitialization delay upon the next invocation.

This PR sets QuitMode::Explicit on the GPUI app to keep the overlay alive in the background, making subsequent ring invocations instant.

Changes

• crates/openlogi-overlay/src/main.rs: added app.with_quit_mode(gpui::QuitMode::Explicit).

Testing

• Verified on Ubuntu 26.04. The Actions Ring now closes properly and re-opens instantly without tearing down the overlay process.

Fixes # (no issue, observed locally)

[greptile-apps]

Greptile Summary

The PR configures the GPUI overlay to quit only explicitly, allowing the process to remain warm after its Actions Ring window closes.

• Sets gpui::QuitMode::Explicit before starting the application.
• Preserves the existing IPC reconnection and overlay replacement lifecycle.

Confidence Score: 5/5

The PR appears safe to merge, with no actionable lifecycle or correctness issue identified.

The explicit quit mode keeps the overlay alive between window invocations as intended, while existing IPC reconnection and process-replacement paths continue to manage agent disconnects and overlay succession.

Important Files Changed

Filename	Overview
crates/openlogi-overlay/src/main.rs	Configures explicit application quitting so closing the final overlay window no longer terminates the process; no actionable defect was identified.

_{Reviews (1): Last reviewed commit: "fix(overlay): prevent GPUI from exiting ..." | Re-trigger Greptile}