[codex] support React Router 8 compatibility

[ScriptedAlchemy]

Summary

• Add examples/react-router-8 as a direct copy of React Router’s integration/helpers/vite-8-template, with the Vite config/scripts swapped for this Rsbuild plugin.
• Add Playwright dev and production e2e coverage for the copied React Router 8 default template, including browser console/page-error/request-failure checks.
• Resolve RR8 hydration/runtime compatibility by using React Router’s installed UNSAFE_* route wrapper helpers and aliasing react-router package imports to the app install.
• Include the RR8 example in the repo e2e example filter and document it in the examples table.
• Remove the stale packed version-matrix script/command and consolidate duplicate changesets into one RR8 compatibility changeset.

Validation

• pnpm prettier --write package.json README.md src/index.ts src/plugin-utils.ts src/route-component-transform.ts tests/index.test.ts tests/plugin-utils.test.ts examples/react-router-8/package.json examples/react-router-8/README.md examples/react-router-8/app/root.tsx examples/react-router-8/app/routes.ts examples/react-router-8/app/routes/_index.tsx examples/react-router-8/env.d.ts examples/react-router-8/playwright.config.ts examples/react-router-8/react-router.config.ts examples/react-router-8/rsbuild.config.ts examples/react-router-8/tests/e2e/react-router-8.test.ts examples/react-router-8/tsconfig.json
• pnpm prettier --write package.json .changeset/react-router-8-default-template.md
• git diff --check
• pnpm test:core -- tests/plugin-utils.test.ts tests/index.test.ts
• pnpm test:core -- tests/plugin-utils.test.ts tests/index.test.ts tests/prerender.test.ts tests/react-router-config.test.ts tests/modify-browser-manifest.test.ts
• pnpm --filter react-router-8-default-template typecheck
• pnpm build
• pnpm --filter react-router-8-default-template test:e2e
• pnpm test:package-interop

TraceDecay was used for changed-file impact context; latest diff context mapped the plugin changes to route transform/dev runtime coverage and affected tests.

Note: this PR is stacked on codex/prewarm-route-workers because the worktree started from that branch. Against that base, this branch contains the React Router 8 compatibility/example work.

[github-actions]

Benchmark Results

Compared PR head 3c901d8 against base 3d3d54a.

Dev Rollup

Group	Fixtures	Base total	Head total	Delta	Base ready	Head ready	Ready delta	Base routes	Head routes	Route delta	Base update/HMR	Head update/HMR	Update delta	Speedup
All dev fixtures	7	32.27s	31.47s	-2.5%	20.88s	20.57s	-1.5%	4.02s	3.95s	-1.8%	3.59s	3.27s	-8.9%	1.03x
Large app	1	14.85s	14.83s	-0.2%	8.83s	8.77s	-0.7%	2.05s	2.02s	-1.6%	2.15s	2.13s	-1.2%	1.00x
Standard fixtures	6	17.42s	16.64s	-4.5%	12.05s	11.81s	-2.0%	1.96s	1.92s	-2.0%	1.44s	1.14s	-20.6%	1.05x

Production Build Benchmarks

Rendered 7 production build benchmarks.

Benchmark	Runs	Base total	Head total	Delta	Head mean	Head p95	Speedup	Head RSS p95
large-355-ssr-esm	5	9.85s	9.70s	-1.5%	9.67s	9.95s	1.02x	1548 MB
synthetic-1024-ssr-esm	5	4.90s	4.57s	-6.7%	4.61s	4.77s	1.07x	636 MB
synthetic-1024-ssr-esm-split	5	6.34s	5.84s	-7.8%	5.84s	6.05s	1.08x	820 MB
synthetic-256-sourcemaps	10	3.00s	2.84s	-5.1%	2.87s	3.09s	1.05x	499 MB
synthetic-256-ssr-esm	10	2.86s	2.76s	-3.2%	2.78s	2.95s	1.03x	458 MB
synthetic-256-ssr-esm-split	10	3.28s	3.14s	-4.2%	3.14s	3.29s	1.04x	494 MB
synthetic-48-ssr-esm	10	1.91s	1.84s	-4.0%	1.88s	2.24s	1.04x	346 MB

full Dev Fixture Summary

Rendered 7 dev benchmark fixtures from the full profile.

Benchmark	Runs	Base total	Head total	Delta	Base ready	Head ready	Base routes	Head routes	Base update/HMR	Head update/HMR	Update delta	Head mean	Head p95	Speedup	Head RSS p95
large-355-ssr-esm	5	14.85s	14.83s	-0.2%	8.83s	8.77s	2.05s	2.02s	2.15s	2.13s	-1.2%	14.76s	14.96s	1.00x	-
synthetic-1024-ssr-esm	5	4.76s	4.51s	-5.3%	3.11s	3.04s	0.55s	0.55s	0.48s	0.38s	-20.4%	4.51s	4.59s	1.06x	-
synthetic-1024-ssr-esm-split	5	4.86s	4.53s	-6.7%	3.15s	3.08s	0.55s	0.54s	0.50s	0.38s	-24.7%	4.53s	4.61s	1.07x	-
synthetic-256-sourcemaps	10	2.38s	2.34s	-1.6%	1.79s	1.76s	0.25s	0.23s	0.15s	0.13s	-16.4%	2.33s	2.38s	1.02x	-
synthetic-256-ssr-esm	10	2.15s	2.09s	-2.7%	1.58s	1.55s	0.24s	0.24s	0.13s	0.10s	-19.9%	2.09s	2.17s	1.03x	-
synthetic-256-ssr-esm-split	10	2.18s	2.09s	-4.2%	1.60s	1.55s	0.24s	0.24s	0.13s	0.10s	-19.0%	2.08s	2.14s	1.04x	-
synthetic-48-ssr-esm	10	1.10s	1.09s	-1.0%	0.82s	0.83s	0.13s	0.13s	0.05s	0.05s	+0.5%	1.09s	1.14s	1.01x	-

Synthetic Rsbuild App

Rendered 2 production build benchmarks.

Benchmark	Runs	Base total	Head total	Delta	Head mean	Head p95	Speedup	Head RSS p95
complex app	2	115.18s	105.82s	-8.1%	105.82s	-	1.09x	-
complex app	2	106.31s	102.14s	-3.9%	102.14s	-	1.04x	-

Rendered 1 dev benchmark fixture from the embedded complex app.

Benchmark	Runs	Base total	Head total	Delta	Base ready	Head ready	Base routes	Head routes	Base update/HMR	Head update/HMR	Update delta	Head mean	Head p95	Speedup	Head RSS p95
complex app	2	86.85s	85.37s	-1.7%	77.50s	75.98s	2.78s	2.73s	4.29s	4.40s	+2.5%	85.37s	-	1.02x	-

Profile: full; mode: dev; iterations: 10; warmup: 0.
Workflow run