CUB-183: SQLite schema migration + DB init

internal/db/migrations/001_create_tables.sql

@@ -0,0 +1,57 @@
+-- RemoteRig Database Schema (SQLite)
+-- Migration: 001_create_tables
+
+-- Cameras table: registry of all GoPro cameras
+CREATE TABLE IF NOT EXISTS cameras (
+    camera_id     TEXT PRIMARY KEY,
+    friendly_name TEXT NOT NULL,
+    mac_address   TEXT UNIQUE,
+    created_at    DATETIME NOT NULL DEFAULT (datetime('now')),
+    updated_at    DATETIME NOT NULL DEFAULT (datetime('now'))
+);
+
+CREATE INDEX IF NOT EXISTS idx_cameras_mac ON cameras(mac_address);
+
+-- Status logs: every poll from an ESP8266 node
+CREATE TABLE IF NOT EXISTS status_logs (
+    id                  INTEGER PRIMARY KEY AUTOINCREMENT,
+    camera_id           TEXT NOT NULL REFERENCES cameras(camera_id),
+    recorded_at         DATETIME NOT NULL DEFAULT (datetime('now')),
+    battery_pct         INTEGER,
+    video_remaining_sec INTEGER,
+    recording_state     INTEGER NOT NULL DEFAULT 0,
+    mode                TEXT,
+    resolution          TEXT,
+    fps                 INTEGER,
+    online              INTEGER NOT NULL DEFAULT 1,
+    raw_battery_pct     REAL
+);
+
+CREATE INDEX IF NOT EXISTS idx_status_logs_camera_time
+    ON status_logs(camera_id, recorded_at DESC);
+
+-- Recording events: explicit start/stop events
+CREATE TABLE IF NOT EXISTS recording_events (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    camera_id   TEXT NOT NULL REFERENCES cameras(camera_id),
+    started_at  DATETIME NOT NULL,
+    stopped_at  DATETIME,
+    reason      TEXT,
+    duration    INTEGER
+);
+
+CREATE INDEX IF NOT EXISTS idx_recording_events_camera_time
+    ON recording_events(camera_id, started_at DESC);
+
+-- Settings: system-wide and per-camera config
+CREATE TABLE IF NOT EXISTS settings (
+    key        TEXT PRIMARY KEY,
+    value      TEXT NOT NULL,
+    updated_at DATETIME NOT NULL DEFAULT (datetime('now'))
+);
+
+-- Seed: default poll interval and thresholds
+INSERT INTO settings (key, value) VALUES
+    ('poll_interval_sec', '30'),
+    ('low_battery_threshold', '15'),
+    ('low_storage_alert_sec', '300');