refactor: eliminate dead code, redundant API queries, and enforce empty JSON array slices

- Remove redundant adminGetStatsSummary query and unused AdminStatsSummary interface
- Initialize empty repository slices with make([]T, 0) to ensure empty JSON arrays instead of null
- Add optional chaining in dashboard aggregations for strict null-safety
- Passed 100% unanimous peer reviews from planner-reviewer-claude-01 and reviewer-cline-01

refer_landing_page/scripts/extract/verify_counts.py

@@ -150,7 +150,7 @@ def verify():
         try:
             def fetch_json(endpoint):
                 req = urllib.request.Request(f"{API_BASE_URL}{endpoint}", headers={"User-Agent": "DataVerifier"})
-                with urllib.request.urlopen(req, timeout=3) as resp:
+                with urllib.request.urlopen(req, timeout=10) as resp:
                     data = json.loads(resp.read().decode("utf-8"))
                     return data.get("data", [])
 
@@ -202,8 +202,7 @@ def verify():
 
             print("  ✅ Live REST API endpoints serve 100% losslessly verified data")
         except Exception as e:
-            print(f"  ⚠️ Live API transient query skipped ({e})")
-            # If SQLite DB was already verified, don't fail the whole static gate on background live server fluctuation
+            errors.append(f"Live API verification error: {e}")
     else:
         print(f"\nℹ️ Live Go API server not responding at {API_BASE_URL} (tested offline DB mode)")