build: migrate examples to vite

[kpal81xd]

Description

Migrate the examples browser build from Rollup/concurrently/serve to Vite and esbuild, while keeping the examples build commands routed through a single examples/build.mjs entry point.

• Adds Vite for the examples app development server, preview server, and production app bundle.
• Uses esbuild for bundled example support modules and the root engine esbuild helper for examples engine bundles.
• Moves examples build helpers into examples/utils with clearer names and typed JSDoc.
• Generates metadata before production builds, type checks, and thumbnail generation.
• Splits examples TypeScript configs so app code and example code can be checked separately.
• Makes the default examples development command disable automatic browser and iframe reloads.
• Adds npm run dev for reload-enabled Vite development.
• Preserves clean share preview routes such as /share/misc_hello-world and /share/misc_hello-world/.

npm scripts

Script	Change
build	Runs cross-env NODE_ENV=production node build.mjs.
build:metadata	Runs node build.mjs --metadata.
build:thumbnails	Runs node build.mjs --thumbnails.
clean	Runs node build.mjs --clean.
dev	Generates metadata and starts Vite with automatic reloads enabled.
develop	Generates metadata and starts Vite with automatic reloads disabled.
serve	Uses vite preview.
type:check	Runs app and examples type checks.
type:check:app	Generates metadata and checks app code with tsconfig.app.json.
type:check:examples	Checks example code with tsconfig.examples.json.

The old Rollup watch flow was removed; Vite now handles development rebuilds.

Notes

• Public engine API changes: none.
• Examples output paths remain under examples/dist.
• /, /playcanvas.d.ts, /iframe/*.html, and /share/* routes are preserved for preview output.
• examples/scripts is removed; reusable build logic now lives in examples/utils.
• npm run develop disables Vite HMR and suppresses the custom examples iframe reload event; manual browser refresh still serves updated files.
• npm run dev keeps the reload-enabled Vite development behavior.
• No examples Turbo tasks are added. Examples remain an isolated package rather than a root workspace package.
• build:thumbnails is still available but continues to launch Puppeteer and write thumbnail output.

Build comparison

Area	Main	This branch	Result
Files	1868	1869	Branch only adds root dist/playcanvas.d.ts.
Logical size	491.6 MB	489.8 MB	Branch output is smaller overall.
Copied static/modules/share/thumbnails	Byte-identical	Byte-identical	No copied asset differences found.
Example metadata	213 entries	213 entries	Matches excluding temp worktree paths.
Engine iframe bundles	Rollup output	esbuild output	Same bundle names; generated bundles are smaller on this branch.

Manual validation

• Ran cd examples && npm run build:metadata.
• Ran cd examples && npm run lint.
• Ran cd examples && npm run type:check.
• Ran cd examples && npm run build.
• Ran cd examples && npm run dev -- --version.
• Ran cd examples && npm run develop -- --version.
• Config-loaded vite.config.mjs with EXAMPLES_AUTO_RELOAD=false and without it to confirm reloads default on and disable when requested.
• Compared examples/dist output from main and this branch in detached worktrees; no files present on main were missing on this branch.
• Smoke-tested Vite preview routes: /, /playcanvas.d.ts, /iframe/misc_hello-world.html, /static/lib/basis/basis.wasm.js, /share/misc_hello-world, /share/misc_hello-world/, and /share/misc_hello-world/index.html.
• Rebased the branch onto current main after the engine build PR merged and force-pushed with lease.

Checklist

• I have read the contributing guidelines
• My code follows the project coding standards
• This PR focuses on a single change