Localize QNA (Q&A) support pages

Replace all hardcoded Korean text with i18n translation keys in
QNA detail and register pages. List page was already localized.

Translation keys added to en.json:
- detailLabels: title, type, registrationDate, answerDate,
  inquiryAnswer, inquiryContents
- formLabels: title, inquiryType, requesterName, phoneNumber,
  emailAddress, inquiryContents, required marker, placeholders
- submitButton, confirmButton, successMessage

Components localized:
- detail-page.tsx: All label badges for title, type, dates, and
  section titles for answer/contents
- register-page.tsx: All form field labels, placeholders, dialog
  button, success alert, and submit button

Note: list-page.tsx was already fully localized.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/locales/en.json

@@ -232,7 +232,29 @@
                 "requestTel": "Phone number is required.",
                 "requestEmail": "Invalid email type.",
                 "contents": "Contents is required."
-            }
+            },
+            "detailLabels": {
+                "title": "Title",
+                "type": "Type",
+                "registrationDate": "Registration Date",
+                "answerDate": "Answer Date",
+                "inquiryAnswer": "Inquiry Answer",
+                "inquiryContents": "Inquiry Contents"
+            },
+            "formLabels": {
+                "title": "Title",
+                "inquiryType": "Inquiry Type",
+                "requesterName": "Requester Name",
+                "phoneNumber": "Phone Number",
+                "emailAddress": "Email Address",
+                "inquiryContents": "Inquiry Contents",
+                "required": "*",
+                "phonePlaceholder": "Enter without '-'",
+                "emailPlaceholder": "TEST123@nicepay.com"
+            },
+            "submitButton": "Submit",
+            "confirmButton": "Confirm",
+            "successMessage": "Success"
         }
     },
     "slideMenu": {