Fix Stack Overflow crawling platform name mismatch

The issue was that Stack Overflow was configured with platform name
'stackoverflow' but the data collection code expected 'stackexchange'.
Fixed by:

1. Renamed platform from 'stackoverflow' to 'stackexchange' in platform_config.json
2. Added Stack Overflow collection target to enable crawling
3. Updated templates and app.py to use the correct platform name
4. Added default 'stackoverflow' community alongside existing featured/newest

This resolves the platform name mismatch that prevented Stack Overflow
from being crawlable.

Fixes #23

~claude

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

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

app.py

@@ -1155,7 +1155,7 @@ def settings_communities():
         {'id': 'technology', 'name': 'Technology', 'platform': 'reddit'},
         {'id': 'hackernews', 'name': 'Hacker News', 'platform': 'hackernews'},
         {'id': 'lobsters', 'name': 'Lobsters', 'platform': 'lobsters'},
-        {'id': 'stackoverflow', 'name': 'Stack Overflow', 'platform': 'stackoverflow'},
+        {'id': 'stackoverflow', 'name': 'Stack Overflow', 'platform': 'stackexchange'},
     ]
     
     return render_template('settings_communities.html', 

platform_config.json

@@ -143,13 +143,20 @@
         }
       ]
     },
-    "stackoverflow": {
+    "stackexchange": {
       "name": "Stack Overflow",
       "icon": "📚",
       "color": "#f48024",
       "prefix": "",
       "supports_communities": false,
       "communities": [
+        {
+          "id": "stackoverflow",
+          "name": "Stack Overflow",
+          "display_name": "Stack Overflow",
+          "icon": "📚",
+          "description": "Programming Q&A community"
+        },
         {
           "id": "featured",
           "name": "Featured",
@@ -257,6 +264,12 @@
       "community": "https://hnrss.org/frontpage",
       "max_posts": 50,
       "priority": "low"
+    },
+    {
+      "platform": "stackexchange",
+      "community": "stackoverflow",
+      "max_posts": 50,
+      "priority": "medium"
     }
   ]
 }

templates/post_detail.html

@@ -105,7 +105,7 @@
                         🐙 View on GitHub
                     {% elif post.platform == 'devto' %}
                         📝 View on Dev.to
-                    {% elif post.platform == 'stackoverflow' %}
+                    {% elif post.platform == 'stackexchange' %}
                         📚 View on Stack Overflow
                     {% else %}
                         🔗 View Original Source

templates/settings_communities.html

@@ -79,7 +79,7 @@
     .platform-icon.reddit { background: #ff4500; }
     .platform-icon.hackernews { background: #ff6600; }
     .platform-icon.lobsters { background: #ac130d; }
-    .platform-icon.stackoverflow { background: #f48024; }
+    .platform-icon.stackexchange { background: #f48024; }
 
     .community-grid {
         display: grid;
@@ -269,7 +269,7 @@
                 <div class="platform-group">
                     <h3>
                         <span class="platform-icon {{ platform }}">
-                            {% if platform == 'reddit' %}R{% elif platform == 'hackernews' %}H{% elif platform == 'lobsters' %}L{% elif platform == 'stackoverflow' %}S{% endif %}
+                            {% if platform == 'reddit' %}R{% elif platform == 'hackernews' %}H{% elif platform == 'lobsters' %}L{% elif platform == 'stackexchange' %}S{% endif %}
                         </span>
                         {{ platform|title }}
                     </h3>