Stabilize app live run activity

[yvette-carlisle]

Summary:

• Keep desktop app live runActivity overlaid across newer empty operator snapshots to prevent Running/pill flicker.
• Let empty complete runActivity still clear real idle state.
• Pin lane popover project name to the top-right side of the header.

Verification:

• swift test --package-path apps/decodex-app --filter AccountModelTests
• swift test --package-path apps/decodex-app
• cargo make test-decodex-app-stage
• git diff --check
• codesign --verify --deep --strict target/decodex-app/Decodex App.app