feat: East Africa + Southern Africa pills with regional sub-sections

- East Africa pill: merges Uganda + east-africa tags; Uganda pinned first via sub-sections
- Southern Africa pill: covers SA, Namibia, Botswana, Zimbabwe, Zambia, Mozambique; SA/Namibia/Botswana prioritized
- StoryStore.setPill now resets lastSyncedAt to bypass 30s rate-limit on filter switch
- sectionSupplement background fetch populates sparse regional sections in All digest
- SignalFeedView digestContent: flat hero+scroll path for pills without subSections (was showing max 5)
- Theme: removed standalone Uganda pill, wired new sub-section layouts

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Jarvis/Connectivity/ConnectivityManager.swift

@@ -106,6 +106,8 @@ final class ConnectivityManager: ObservableObject {
         guard host != lastActivated else { return }   // avoid thrashing the WS
         lastActivated = host
         await ServerSettings.shared.activate(host: host)
-        await StoryStore.shared.loadStories(refresh: true)
+        // Full paginated load — page 1 only misses unread stories on pages 2–5
+        // that may have arrived since last session.
+        await StoryStore.shared.loadFeedFull()
     }
 }