fix: prevent hydration mismatch in useHeatmapTheme by suppressing mismatch on theme element

[tmdeveloper007]

fix: prevent hydration mismatch in useHeatmapTheme by suppressing mismatch on theme element

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[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

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• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

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Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Priyanshu-byte-coder]

Missing EOF newline on e2e/landing.spec.js. Also: the returned suppressHydrationMismatch flag is not used by any call site — either apply suppressHydrationWarning in the component that consumes this hook, or remove the flag from the return value.

[Priyanshu-byte-coder]

One issue to fix:

Missing EOF newline in e2e/landing.spec.js
The diff shows -});\n+});\ No newline at end of file — your change removes the trailing newline from the file. All files must end with a newline. Please restore it.

The hydration mismatch fix itself (mounted state, returning "default" until mounted) is correct and the approach is good.

[tmdeveloper007]

This pull request is fully up-to-date with the latest upstream merges, all review items are addressed, local tests are passing cleanly, and it is fully ready to be merged! 🚀