[Stimulus] Lock the deterministic local controller ordering with a test

Port symfony/ux#3703. Reprise already sorts local controllers (listLocalControllers
ends with `.sort()`), so the generated module is deterministic today; add a regression
test asserting the exact emission order and a comment documenting why the sort matters
(stable content hash regardless of filesystem iteration order).

Author: Kocal

assets/src/core/stimulus.ts

@@ -175,10 +175,14 @@ function listLocalControllers(dir: string): string[] {
     } catch {
         return []; // dir absent -> no local controllers
     }
-    return entries
-        .map((e) => String(e).replace(/\\/g, '/'))
-        .filter((e) => LOCAL_CONTROLLER_RE.test(e))
-        .sort();
+    return (
+        entries
+            .map((e) => String(e).replace(/\\/g, '/'))
+            .filter((e) => LOCAL_CONTROLLER_RE.test(e))
+            // Sort so the generated module -- and therefore its content hash -- stays stable
+            // regardless of the filesystem's iteration order. See symfony/ux#3703.
+            .sort()
+    );
 }
 
 function localIdentifier(rel: string): string {

assets/test/core/stimulus.test.ts

@@ -86,6 +86,25 @@ describe('generateControllersModule — local', () => {
         expect(src).toContain('export const lazyControllers = {}');
     });
 
+    it('emits controllers in a stable, name-sorted order (deterministic output/hash)', () => {
+        // Local controllers are sorted by filename so the generated module -- and thus its
+        // content hash -- stays stable regardless of the order the filesystem returns the files
+        // in (symfony/ux#3703). Assert the exact identifier order the module is rendered in.
+        const src = generateControllersModule(localOpts, root, false);
+        const identifiers = [...src.matchAll(/^ {2}"([^"]+)":/gm)].map((m) => m[1]);
+        expect(identifiers).toEqual([
+            // eagerControllers: third-party first, then local controllers sorted by filename
+            'acme--ux-hello--hello',
+            'above-imports',
+            'admin--user',
+            'greet',
+            // lazyControllers: third-party first, then local controllers sorted by filename
+            'acme--ux-map--map',
+            'heavy',
+            'preserved-comment',
+            'single-line',
+        ]);
+    });
 });
 
 describe('generateControllersModule — identifier collision', () => {