perf(weather): wake a staged frame on a 150 ms timer, not every render (#1345)

Wake staged weather imagery on a bounded timer instead of requesting every render.

Contribution by @nu-stats.

changelog.d/1345-weather-staging-wake.md

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+- Wake staged weather imagery on a 150 ms timer while waiting for readiness,
+  avoiding a continuous render loop and cancelling the wake when work ends
+  (@nu-stats, #1345).