Fix: millis() overflow using PollingTimer

[hideakitai]

Fix #127

[Copilot]

Pull Request Overview

This PR fixes a millis() overflow issue by replacing Arduino's millis() function with the PollingTimer library for more robust time tracking in Art-Net streaming operations.

• Adds PollingTimer as a dependency to handle timing without overflow issues
• Replaces uint32_t time tracking with double precision timing from PollingTimer
• Updates time interval calculations to use floating-point arithmetic

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
library.properties	Adds PollingTimer as a required dependency
library.json	Adds PollingTimer dependency with version wildcard
Artnet/Sender.h	Integrates PollingTimer for time tracking in streaming methods
Artnet/Common.h	Updates interval constant and time map to use double precision

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