feat: Refactors the 3d-camera-boundary sample to latest standards.

[willum070]

This PR does the following things:

• Refactors the 3d-camera-boundary sample to latest standards.
• Replaces the <div id="map"></div> element in index.html with a <gmp-map-3d> web component.
• Removes unused CSS rules.
• Bumps copyrights to 2026.
• Removes empty dependencies section from package.json.

Key changes:

Migration to web component:

• Replaces the <div id="map"></div> element in index.html with a <gmp-map-3d> web component, setting its initial center, tilt, mode, and gesture handling via attributes. (samples/3d-camera-boundary/index.html samples/3d-camera-boundary/index.htmlL22-R28)
• Updates index.ts to select the gmp-map-3d element and set its bounds property directly, removing the previous instantiation of Map3DElement in JavaScript. (samples/3d-camera-boundary/index.ts samples/3d-camera-boundary/index.tsL3-R19)

Code and dependency cleanup:

• Removes unused CSS rules for the old map div, leaving only essential styling. (samples/3d-camera-boundary/style.css samples/3d-camera-boundary/style.cssL3-L14)
• Cleans up package.json by removing the empty dependencies section. (samples/3d-camera-boundary/package.json samples/3d-camera-boundary/package.jsonL10-L12)

Other updates:

• Updates copyright years from 2025 to 2026 in all files. (samples/3d-camera-boundary/index.html [1] samples/3d-camera-boundary/index.ts [2] samples/3d-camera-boundary/style.css [3]