Enhance CLI Build Duration Output with Human-Readable Formatting

[wangfu91]

This pull request enhances the display of build durations in the terminal by adopting a more user-friendly formatting style.

The change replaces raw millisecond values with formatted durations using the humantime crate, making it easier to read and interpret.

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After:

[Copilot]

Pull Request Overview

This PR enhances the CLI build duration output by replacing raw millisecond values with human-readable formatting using the humantime crate. This improves user experience by making build durations easier to interpret.

Key Changes

• Replaces millisecond duration output with human-readable format (e.g., "1.5s" instead of "1500ms")
• Adds the humantime dependency to format durations with millisecond precision
• Updates two build completion log messages in the CLI runner

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 3 comments.

File	Description
packages/cli/src/serve/runner.rs	Updates build completion logging to use human-readable duration formatting
packages/cli/Cargo.toml	Adds humantime dependency for duration formatting

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