Add buttons, menus and the rest of M3 Expressive's actions

<x-button> (label buttons, icon buttons and toggles in five sizes, with
filled, tonal, outlined, elevated and text variants in any colour role),
<x-tooltip>, <x-menu> with items, groups and separators, <x-button-group>,
<x-group> as a connected button group, <x-split-button>, <x-fab>,
<x-fab-menu> and <x-loading>. Sizes, colours and shapes come from
androidx Compose Material 3's tokens; the loading indicator ports its
Morph into SVG + SMIL.

Menus follow WAI-ARIA's menu button pattern on popovers placed by CSS
anchor positioning. Browser tests run in Chromium, Firefox and WebKit.
The showcase fetches the icon names on demand: inlined, they tripped
Pest's test server into HTTP 431s under Firefox.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

bin/shapes.mjs

@@ -42,8 +42,9 @@
  * limitations under the License.
  * ---------------------------------------------------------------------------------------
  */
-import { mkdirSync, readdirSync, rmSync, writeFileSync } from 'node:fs'
+import { mkdirSync, readdirSync, realpathSync, rmSync, writeFileSync } from 'node:fs'
 import { join } from 'node:path'
+import { fileURLToPath } from 'node:url'
 
 const OUTPUT = 'resources/svg/shapes'
 const VIEWBOX = 100
@@ -864,18 +865,23 @@ function pathData(polygon) {
     return `${d}Z`
 }
 
-mkdirSync(OUTPUT, { recursive: true })
+/** The geometry, for other build scripts (bin/loading-indicator.mjs); importing this module writes nothing. */
+export { point, pointOnCurve, split, cubicBounds, RoundedPolygon, SHAPES }
 
-for (const file of readdirSync(OUTPUT)) {
-    if (file.endsWith('.svg')) {
-        rmSync(join(OUTPUT, file))
+if (process.argv[1] !== undefined && realpathSync(process.argv[1]) === fileURLToPath(import.meta.url)) {
+    mkdirSync(OUTPUT, { recursive: true })
+
+    for (const file of readdirSync(OUTPUT)) {
+        if (file.endsWith('.svg')) {
+            rmSync(join(OUTPUT, file))
+        }
     }
+
+    for (const [name, build] of Object.entries(SHAPES)) {
+        const svg = `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 ${VIEWBOX} ${VIEWBOX}" fill="currentColor"><path d="${pathData(fitted(build().normalized()))}"/></svg>\n`
+
+        writeFileSync(join(OUTPUT, `${name}.svg`), svg)
+    }
+
+    console.log(`Wrote ${Object.keys(SHAPES).length} shapes to ${OUTPUT}`)
 }
-
-for (const [name, build] of Object.entries(SHAPES)) {
-    const svg = `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 ${VIEWBOX} ${VIEWBOX}" fill="currentColor"><path d="${pathData(fitted(build().normalized()))}"/></svg>\n`
-
-    writeFileSync(join(OUTPUT, `${name}.svg`), svg)
-}
-
-console.log(`Wrote ${Object.keys(SHAPES).length} shapes to ${OUTPUT}`)