Revert "Add presence DB schema; fix BLE passive scan mode (bleak #1440)"

This reverts commit 2499db6147be65c76e7e202190b81855ba7b9100.

net_alerter/ble_alerter.py

@@ -274,8 +274,8 @@ async def scan_loop():
         
         await on_arrival(name, mac, rssi)
     
-    # Passive scanner — required to avoid corrupting BLE 0x004C manufacturer_data (bleak #1440)
-    async with BleakScanner(detection_callback=detection_callback, scanning_mode="passive") as scanner:
+    # Active scanner — explicitly required; bleak 0.20 BlueZ backend defaults to passive
+    async with BleakScanner(detection_callback=detection_callback, scanning_mode="active") as scanner:
         try:
             while not shutdown_event.is_set():
                 await asyncio.sleep(1)

net_alerter/presence_schema.sql

@@ -1,38 +0,0 @@
--- Presence intelligence schema — Phase 1 (WiFi-only)
--- Load with: sqlite3 presence.db < presence_schema.sql
-
-PRAGMA journal_mode=WAL;
-
-CREATE TABLE IF NOT EXISTS persons (
-    mac TEXT PRIMARY KEY,
-    hostname TEXT,
-    vendor TEXT,
-    first_seen REAL NOT NULL,
-    last_seen REAL NOT NULL,
-    state TEXT NOT NULL DEFAULT 'ABSENT',
-    certainty REAL NOT NULL DEFAULT 0.0,
-    session_count INTEGER NOT NULL DEFAULT 1,
-    total_minutes REAL NOT NULL DEFAULT 0.0
-);
-
-CREATE TABLE IF NOT EXISTS signals (
-    id INTEGER PRIMARY KEY AUTOINCREMENT,
-    mac TEXT NOT NULL,
-    signal_type TEXT NOT NULL,  -- mdns | arp
-    certainty REAL NOT NULL,
-    observed_at REAL NOT NULL
-);
-
-CREATE TABLE IF NOT EXISTS events (
-    id INTEGER PRIMARY KEY AUTOINCREMENT,
-    mac TEXT NOT NULL,
-    hostname TEXT,
-    event_type TEXT NOT NULL,  -- arrived | departed | updated
-    certainty REAL NOT NULL,
-    timestamp REAL NOT NULL
-);
-
-CREATE INDEX IF NOT EXISTS idx_signals_mac ON signals(mac);
-CREATE INDEX IF NOT EXISTS idx_signals_mac_time ON signals(mac, observed_at);
-CREATE INDEX IF NOT EXISTS idx_events_mac ON events(mac);
-CREATE INDEX IF NOT EXISTS idx_events_timestamp ON events(timestamp);