feat: implement in-memory caching for dashboard data and background warmup task

src/tasks/dashboard_warmup.py

@@ -0,0 +1,68 @@
+# tasks/dashboard_warmup.py
+
+"""
+Pre-computes all Overview tab data and stores it in the in-memory cache.
+This keeps SQLite page buffers warm and lets the dashboard respond instantly.
+"""
+
+from logger import get_app_logger
+from database import get_database
+from dashboard_cache import set_cached
+
+app_logger = get_app_logger()
+
+# ----------------------
+# TASK CONFIG
+# ----------------------
+TASK_CONFIG = {
+    "name": "dashboard-warmup",
+    "cron": "*/1 * * * *",
+    "enabled": True,
+    "run_when_loaded": True,
+}
+
+
+# ----------------------
+# TASK LOGIC
+# ----------------------
+def main():
+    """
+    Refresh the in-memory dashboard cache with current Overview data.
+    TasksMaster will call this function based on the cron schedule.
+    """
+    task_name = TASK_CONFIG.get("name")
+    app_logger.info(f"[Background Task] {task_name} starting...")
+
+    try:
+        db = get_database()
+
+        # --- Server-rendered data (stats cards + suspicious table) ---
+        stats = db.get_dashboard_counts()
+
+        cred_result = db.get_credentials_paginated(page=1, page_size=1)
+        stats["credential_count"] = cred_result["pagination"]["total"]
+
+        suspicious = db.get_recent_suspicious(limit=10)
+
+        # --- HTMX Overview tables (first page, default sort) ---
+        top_ips = db.get_top_ips_paginated(page=1, page_size=8)
+        top_ua = db.get_top_user_agents_paginated(page=1, page_size=5)
+        top_paths = db.get_top_paths_paginated(page=1, page_size=5)
+
+        # --- Map data (default: top 100 IPs by total_requests) ---
+        map_ips = db.get_all_ips_paginated(
+            page=1, page_size=100, sort_by="total_requests", sort_order="desc"
+        )
+
+        # Store everything in the cache (overwrites previous values)
+        set_cached("stats", stats)
+        set_cached("suspicious", suspicious)
+        set_cached("top_ips", top_ips)
+        set_cached("top_ua", top_ua)
+        set_cached("top_paths", top_paths)
+        set_cached("map_ips", map_ips)
+
+        app_logger.info(f"[Background Task] {task_name} cache refreshed successfully.")
+
+    except Exception as e:
+        app_logger.error(f"[Background Task] {task_name} failed: {e}")