feat: 애플 로그인 네이티브 연동 (Sign in with Apple)

@capacitor-community/apple-sign-in 으로 identityToken 획득 → /api/auth/apple.
애플 버튼은 네이티브 iOS 에서만 노출, 시트 취소는 무시.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -8,6 +8,7 @@
       "name": "dognation_pt",
       "version": "0.0.1",
       "dependencies": {
+        "@capacitor-community/apple-sign-in": "^7.1.0",
         "@capacitor/app": "^8.0.0",
         "@capacitor/core": "^8.3.4",
         "@quasar/extras": "^1.16.12",
@@ -83,6 +84,19 @@
       "dev": true,
       "license": "(Apache-2.0 AND BSD-3-Clause)"
     },
+    "node_modules/@capacitor-community/apple-sign-in": {
+      "version": "7.1.0",
+      "resolved": "https://registry.npmjs.org/@capacitor-community/apple-sign-in/-/apple-sign-in-7.1.0.tgz",
+      "integrity": "sha512-df7cA7vfvvvilTtpJKeVvxO31W+py5t3HK9233GBD5MvgAgtGvCqeQ3pI0noNkVsKPF9B1g/po8Mph6s4bVSmw==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/scriptjs": "0.0.2",
+        "scriptjs": "^2.5.9"
+      },
+      "peerDependencies": {
+        "@capacitor/core": ">=7.0.0"
+      }
+    },
     "node_modules/@capacitor/android": {
       "version": "8.4.1",
       "resolved": "https://registry.npmjs.org/@capacitor/android/-/android-8.4.1.tgz",
@@ -1560,6 +1574,12 @@
         "undici-types": "~8.3.0"
       }
     },
+    "node_modules/@types/scriptjs": {
+      "version": "0.0.2",
+      "resolved": "https://registry.npmjs.org/@types/scriptjs/-/scriptjs-0.0.2.tgz",
+      "integrity": "sha512-GFrUgzGYfNX3VWZwMyzr0JrBwzLv5Kes4BQBvo6hXdRy14/GBbpCiVwwB7v1o2xIEvFf+9GyznmYhuesQQjSag==",
+      "license": "MIT"
+    },
     "node_modules/@types/slice-ansi": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/@types/slice-ansi/-/slice-ansi-4.0.0.tgz",
@@ -3191,6 +3211,12 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/scriptjs": {
+      "version": "2.5.9",
+      "resolved": "https://registry.npmjs.org/scriptjs/-/scriptjs-2.5.9.tgz",
+      "integrity": "sha512-qGVDoreyYiP1pkQnbnFAUIS5AjenNwwQBdl7zeos9etl+hYKWahjRTfzAZZYBv5xNHx7vNKCmaLDQZ6Fr2AEXg==",
+      "license": "MIT"
+    },
     "node_modules/semver": {
       "version": "7.8.5",
       "resolved": "https://registry.npmjs.org/semver/-/semver-7.8.5.tgz",