Fix home screen summary showing zeros

The setAllTasks() function was not calling refreshSummaryFromKanban()
after loading kanban data, so the summary statistics (totalTasks,
totalOverdue, etc.) were never calculated - they stayed at zero.

Also switch API environment back to DEV.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

composeApp/src/commonMain/kotlin/com/example/casera/data/DataManager.kt

@@ -401,6 +401,8 @@ object DataManager {
         _allTasks.value = response
         tasksCacheTime = currentTimeMs()
         updateLastSyncTime()
+        // Refresh summary from kanban data (API no longer returns summary stats)
+        refreshSummaryFromKanban()
         persistToDisk()
     }