Add Meta Facebook Login OAuth and social media attach/publish.

Connect Facebook and Instagram via shared portal Meta App credentials (Facebook Login for Business), and let compose attach DB-stored images/videos with live preview and platform publish.

site/social/urls.py

@@ -17,7 +17,28 @@ urlpatterns = [
         views.linkedin_oauth_callback,
         name="linkedin_oauth_callback",
     ),
+    path(
+        "accounts/facebook/start/",
+        views.facebook_oauth_start,
+        name="facebook_oauth_start",
+    ),
+    path(
+        "accounts/instagram/start/",
+        views.instagram_oauth_start,
+        name="instagram_oauth_start",
+    ),
+    path(
+        "accounts/meta/callback/",
+        views.meta_oauth_callback,
+        name="meta_oauth_callback",
+    ),
+    path(
+        "accounts/meta/callback/complete/",
+        views.meta_oauth_complete,
+        name="meta_oauth_complete",
+    ),
     path("compose/", views.composer, name="composer"),
+    path("media/upload/", views.media_upload, name="media_upload"),
     path("api/generate/", views.api_generate, name="api_generate"),
     path("<uuid:pk>/", views.post_detail, name="post_detail"),
 ]