docs: reorganize README around framework mode

[SyMind]

Summary

• Reposition the plugin as a React Router Framework Mode integration for Rsbuild.
• Document the supported Framework Mode conventions and standard project structure more prominently.
• Simplify the Cloudflare deployment section by linking to the tested example.
• Remove duplicated content and reorganize local development instructions.
• Clarify lazy compilation and parallel route transform configuration.
• Add the experimental RSC Framework Mode example to the examples list.

[pkg-pr-new]

Open in StackBlitz

pnpm add https://pkg.pr.new/rsbuild-plugin-react-router@8b63af4

commit: 8b63af4

[github-actions]

Benchmark results

Case	Base	Head	Delta
build-256-ssr	2165.9 ms	2148.1 ms	-0.8%
dev-48-ssr	911.0 ms	936.6 ms	+2.8%

[codspeed-hq]

Merging this PR will not alter performance

✅ 1 untouched benchmark
⏩ 2 skipped benchmarks¹

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_{Comparing docs/refresh-readme (8b63af4) with main (ae222a3)²}

Footnotes

1. 2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (df208f5) during the generation of this report, so ae222a3 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩