Suspend GPU rendering while minimized

[teloverge]

What changed

• stop the star-map RAF loop and resize paints while minimized or hidden
• preserve renderer state and animation phase across suspension
• observe Tauri minimized state and browser document visibility with cleanup and fail-open behavior
• retain the existing five-minute native background polling cadence
• add lifecycle regressions and an Unreleased changelog entry

Why

Stellr's canvas renderer continuously scheduled GPU-backed frames even when the application was minimized. Background data synchronization should continue sparsely, but invisible visual work should stop.

Impact

Minimized native windows and hidden browser documents no longer render canvas frames. Restoring resumes the same map immediately without remounting or resetting camera, selection, model, flare, ticker, or animation phase.

Root cause

The star-map render loop owned an unconditional requestAnimationFrame chain, while window visibility/minimized state was not connected to the renderer lifecycle.

Validation

• vpr.exe test - 30 files and 236 tests passed
• vpr.exe check - 0 errors and 0 warnings
• vpr.exe build
• cargo.exe fmt --all -- --check
• cargo.exe clippy --workspace --all-targets --locked -- -D warnings
• cargo.exe test --workspace --locked -- --test-threads=1