feat: add update instructions dialog, email notifications, and capture date sorting

- Add Update Instructions Dialog with environment-specific commands (Docker/Git/Standalone)
- Add email notification settings for new version alerts
- Add "Sort by Capture Date" option using EXIF metadata extraction
- Fix E2E tests by loading environment variables via dotenv
- Add test-images/ and backend/*.db to .gitignore

Closes #181

package-lock.json

@@ -11,6 +11,7 @@
       },
       "devDependencies": {
         "@playwright/test": "^1.48.2",
+        "dotenv": "^17.3.1",
         "puppeteer": "^24.17.0"
       }
     },
@@ -561,6 +562,19 @@
       "license": "BSD-3-Clause",
       "peer": true
     },
+    "node_modules/dotenv": {
+      "version": "17.3.1",
+      "resolved": "https://registry.npmjs.org/dotenv/-/dotenv-17.3.1.tgz",
+      "integrity": "sha512-IO8C/dzEb6O3F9/twg6ZLXz164a2fhTnEWb95H23Dm4OuN+92NmEAlTrupP9VW6Jm3sO26tQlqyvyi4CsnY9GA==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "engines": {
+        "node": ">=12"
+      },
+      "funding": {
+        "url": "https://dotenvx.com"
+      }
+    },
     "node_modules/emoji-regex": {
       "version": "8.0.0",
       "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-8.0.0.tgz",