feat: Implement email sending utilities and templates for job notifications

- Added email_service.py for sending emails with SMTP configuration.
- Introduced email_templates.py to render job alert email subjects and bodies.
- Enhanced scraper.py to extract contact information from job listings.
- Updated settings.js to handle negative keyword input validation.
- Created email.html and email_templates.html for managing email subscriptions and templates in the admin interface.
- Modified base.html to include links for email alerts and templates.
- Expanded user settings.html to allow management of negative keywords.
- Updated utils.py to include functions for retrieving negative keywords and email settings.
- Enhanced job filtering logic to exclude jobs containing negative keywords.

config/settings.json

@@ -9,7 +9,7 @@
     }
   },
   "http": {
-    "user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:141.0) Gecko/20100101 Firefox/141.0",
+    "user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:145.0) Gecko/20100101 Firefox/145.0",
     "request_timeout": 30,
     "max_retries": 3,
     "backoff_factor": 2,
@@ -22,7 +22,22 @@
   },
   "scraper": {
     "base_url": "https://{region}.craigslist.org/search/jjj?query={keyword}&sort=rel",
-    "config_dir": "config"
+    "config_dir": "config",
+    "negative_keywords": []
+  },
+  "email": {
+    "enabled": false,
+    "from_address": "jobs@example.com",
+    "recipients": [],
+    "smtp": {
+      "host": "smtp.example.com",
+      "port": 587,
+      "username": "",
+      "password": "",
+      "use_tls": true,
+      "use_ssl": false,
+      "timeout": 30
+    }
   },
   "users": [
     { "username": "anonymous", "is_admin": false, "password": "" },