Polish answer notifications and editing controls.

Brand notification emails, log accepted sends, and keep answer editing collapsed until explicitly opened.

internal/web/server_test.go

@@ -601,10 +601,32 @@ func TestMutationsVoteAnswerHideAndCSRF(t *testing.T) {
 	if rec.Code != 200 || !strings.Contains(rec.Body.String(), "Tighten the nuts") {
 		t.Fatalf("admin answer: %d %s", rec.Code, rec.Body.String())
 	}
+	if body := rec.Body.String(); !strings.Contains(body, `class="answer-editor"`) ||
+		!strings.Contains(body, "<summary>Edit answer</summary>") ||
+		!strings.Contains(body, ">Tighten the nuts.</textarea>") ||
+		!strings.Contains(body, `type="reset" class="btn btn-ghost"`) ||
+		!strings.Contains(body, `removeAttribute('open')`) ||
+		strings.Contains(body, `<details class="answer-editor" open`) {
+		t.Fatalf("admin answer editor is not collapsed and populated: %s", body)
+	}
 	if _, err := mem.GetAnswer(context.Background(), q.ID); err != nil {
 		t.Fatal(err)
 	}
 
+	// The public answer is visible to its author, but editing remains admin-only.
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest(http.MethodGet, "/questions/"+q.ID, nil)
+	for _, c := range userCookies {
+		req.AddCookie(c)
+	}
+	h.ServeHTTP(rec, req)
+	if rec.Code != 200 || !strings.Contains(rec.Body.String(), "Tighten the nuts.") {
+		t.Fatalf("question author cannot see answer: %d %s", rec.Code, rec.Body.String())
+	}
+	if strings.Contains(rec.Body.String(), `class="answer-editor"`) {
+		t.Fatalf("question author can see admin answer editor: %s", rec.Body.String())
+	}
+
 	// Hide invalid id
 	rec = httptest.NewRecorder()
 	req = httptest.NewRequest(http.MethodGet, "/questions/"+q.ID, nil)