Fix live script response encoding (#690)

Declare UTF-8 on the generated live and detector JavaScript responses and cover both endpoints with integration assertions.\n\nAI-assisted: prepared with Codex under @pbakaus direction.

skill/scripts/live-server.mjs

@@ -768,7 +768,7 @@ function createRequestHandler({ detectScript, liveScriptParts }) {
         }),
       });
       res.writeHead(200, {
-        'Content-Type': 'application/javascript',
+        'Content-Type': 'application/javascript; charset=utf-8',
         'Cache-Control': 'no-store, no-cache, must-revalidate, max-age=0',
         'Pragma': 'no-cache',
       });
@@ -777,7 +777,7 @@ function createRequestHandler({ detectScript, liveScriptParts }) {
     }
     if (p === '/detect.js' || p === '/') {
       if (!detectScript) { res.writeHead(404); res.end('Not available'); return; }
-      res.writeHead(200, { 'Content-Type': 'application/javascript' });
+      res.writeHead(200, { 'Content-Type': 'application/javascript; charset=utf-8' });
       res.end(detectScript);
       return;
     }

tests/live-server.test.mjs

@@ -350,7 +350,7 @@ describe('live-server integration', () => {
   it('/live.js serves script with token injected', async () => {
     const res = await fetch(`http://localhost:${server.port}/live.js?token=${server.token}`);
     assert.equal(res.status, 200);
-    assert.equal(res.headers.get('content-type'), 'application/javascript');
+    assert.equal(res.headers.get('content-type'), 'application/javascript; charset=utf-8');
     const text = await res.text();
     assert.ok(text.includes('__IMPECCABLE_TOKEN__'));
     assert.ok(text.includes(server.token));
@@ -545,6 +545,9 @@ colors: {}
     const res = await fetch(`http://localhost:${server.port}/detect.js`);
     // May 404 if detect-antipatterns-browser.js hasn't been built
     assert.ok(res.status === 200 || res.status === 404);
+    if (res.status === 200) {
+      assert.equal(res.headers.get('content-type'), 'application/javascript; charset=utf-8');
+    }
   });
 
   it('/manual-edit-commit runs the batched AI apply path and clears successful entries', async () => {