feat: add React 19 support, shared components, utilities, and CLI tooling

[jontsai]

• Add React 19 support and enhance type definitions
• Add CLI tool (htk) and standardized templates (Makefile, next.config, sitemap)
• Add shared components: GoogleAnalytics, ScrollToTop, BasicPageLayout
• Add ThemeContext with useTheme hook
• Add utility functions: URL helpers, sitemap generation, address formatting, array shuffle (Fisher-Yates), email validation and obfuscation

[Copilot]

Pull request overview

This PR updates the packages/core workspace to support React 19 and expands it into a more complete “core” package by adding shared components, a theme context, utility helpers, and a small CLI + templates meant to standardize consuming Next.js projects.

Changes:

• Rename/publish the core package as @hacktoolkit/nextjs-htk and add CLI binaries (htk, nextjs-htk) plus template assets (Makefile, Next config template, sitemap script).
• Add new shared React components (GA, ScrollToTop, BasicPageLayout) and a ThemeContext with useTheme.
• Add utilities (URLs, email validation/obfuscation, sitemap generation, address formatting, shuffle) and expand type definitions.

Reviewed changes

Copilot reviewed 21 out of 23 changed files in this pull request and generated 19 comments.

Show a summary per file

File	Description
packages/core/tsconfig.json	Replaces root extends with standalone TS config for the core package build.
packages/core/templates/scripts/generate_sitemap.ts	Adds a template script to generate sitemap.xml from htk.config.
packages/core/templates/next.config.mjs.template	Adds a Next.js config template aimed at React 19 + static export.
packages/core/templates/Makefile	Adds a standardized Makefile template for dev/build/deploy workflows.
packages/core/src/utils/urls.ts	Adds URL helper utilities (tel/mailto/maps + query params).
packages/core/src/utils/sitemap.ts	Adds sitemap XML generator utility.
packages/core/src/utils/index.ts	Barrel export for the new utils module.
packages/core/src/utils/email.ts	Adds email validation + obfuscation utilities.
packages/core/src/utils/algo.ts	Adds Fisher–Yates shuffle utility.
packages/core/src/utils/address.ts	Adds address formatting helper.
packages/core/src/types/index.ts	Expands site/config types and adds Page, social media link types, SEO config additions, etc.
packages/core/src/index.ts	Re-exports components, context, and utils from the package entrypoint.
packages/core/src/context/index.ts	Barrel export for context module(s).
packages/core/src/context/ThemeContext.tsx	Adds Theme provider and useTheme hook.
packages/core/src/components/index.ts	Barrel export for shared components.
packages/core/src/components/ScrollToTop.tsx	Adds a client component to show a scroll-to-top button.
packages/core/src/components/GoogleAnalytics.tsx	Adds a client component to load GA via next/script.
packages/core/src/components/BasicPageLayout.tsx	Adds a reusable basic layout component for simple content pages.
packages/core/package.json	Renames the package, adds bin entries, and updates exports.
packages/core/bin/htk.js	Adds CLI implementation for syncing template files.
packages/core/README.md	Documents CLI usage and utility examples.
packages/core/CLI_README.md	Adds standalone CLI documentation.
package-lock.json	Adds/updates lockfile content for the workspace dependency graph.

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