feat(rsc): expose server function metadata

[james-elicx]

Extracted from #1246.

Transform runtimes currently receive directive/export metadata but cannot tell whether an inline function captures bound values or inspect the declared parameter shape without reparsing source.

This adds hasBoundArgs and { count, hasRest } metadata for inline functions, plus parameter metadata for named, variable, local re-export, and default module exports. Focused tests cover closure captures and all supported export forms.

[hi-ogawa]

The "runtime meta" now provides corresponding function ast node, so this should allow custom transform to make use of it instead of specific metadata hasBoundArgs/count/hasRest. Please check out the example here:

vite-plugin-react/packages/plugin-rsc/examples/use-cache-callable/callable-cache-plugin.ts

Lines 44 to 46 in 4b0e3c7

	? transformWrapExport(code, ast, {
	runtime: (value, name, meta) =>
	runtime(value, name, getCacheWrapperOptions(meta)),

vite-plugin-react/packages/plugin-rsc/examples/use-cache-callable/callable-cache-plugin.ts

Lines 125 to 139 in 4b0e3c7

	function getCacheWrapperOptions(
	meta: Pick<ModuleExportMeta, 'valueNode'>,
	): CacheWrapperOptions {
	const node = meta.valueNode
	if (
	node?.type !== 'FunctionDeclaration' &&
	node?.type !== 'FunctionExpression' &&
	node?.type !== 'ArrowFunctionExpression'
	) {
	return {}
	}
	return node.params.at(-1)?.type === 'RestElement'
	? {}
	: { argumentCount: node.params.length }
	}

Please let me know if something still requires from transform utility side.