Add Gauge2 Custom Visualization

[google-labs-jules]

Implemented a new custom visualization gauge2 based on D3 and React.

• Configurable dial color and line width.
• Dynamic field selection logic (defaults to last field).
• Single row gauge rendering with label.
• Multi-row grid rendering (max 10 gauges).
• Fixed max value calculation and webpack config.

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PR created automatically by Jules for task 9955181674599566626 started by @bwebs

[google-labs-jules]

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[bwebs]

@google-labs-jules where's your tests? Did you run the yarn command?

[google-labs-jules]

@google-labs-jules where's your tests? Did you run the yarn command?

I have added unit tests for the Gauge component in packages/gauge2/src/__tests__/Gauge.test.tsx. I used yarn as requested. I verified the tests pass by running yarn jest inside the packages/gauge2 directory.