Automatically update copyright year in documentation footer

[keshav15240]

Summary

Adds a small JavaScript snippet to automatically update the copyright year displayed in the documentation footer.

Changes

• Overrides the MkDocs Material footer in docs/overrides/main.html
• Replaces the hardcoded copyright year with the current year using JavaScript
• Keeps the footer up to date without requiring manual yearly updates

Example

Before:
Copyright © 2025 Google

After:
Copyright © 2026 Google
(and automatically updates in future years)

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