regroup backend and frontend in app folder

app/backend/migrations/000001_init_schema.up.sql

@@ -0,0 +1,25 @@
+CREATE TABLE nodes (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(50) NOT NULL,
+    address VARCHAR(50) NOT NULL,
+    status SMALLINT NOT NULL,
+    last_seen TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE TABLE services (
+    id SERIAL PRIMARY KEY,
+    node_id INTEGER NOT NULL REFERENCES nodes(id) ON DELETE CASCADE,
+    name VARCHAR(50) NOT NULL,
+    status SMALLINT NOT NULL,
+    command TEXT
+);
+
+CREATE TABLE status_records (
+    id SERIAL PRIMARY KEY,
+    service_id INTEGER NOT NULL REFERENCES services(id) ON DELETE CASCADE,
+    status SMALLINT NOT NULL,
+    timestamp TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE INDEX idx_services_node_id ON services(node_id);
+CREATE INDEX idx_status_history ON status_records (service_id, timestamp DESC);

app/backend/migrations/000002_auth_features.up.sql

@@ -0,0 +1,17 @@
+CREATE TABLE users (
+    id SERIAL PRIMARY KEY,
+    username VARCHAR(50) UNIQUE NOT NULL,
+    email VARCHAR(255) UNIQUE NOT NULL,
+    password_hash TEXT NOT NULL,
+    role VARCHAR(20) DEFAULT 'user',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
+    last_login TIMESTAMP WITH TIME ZONE
+);
+
+CREATE TABLE sessions (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+    token TEXT UNIQUE NOT NULL,
+    expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
+);

app/backend/migrations/000003_api_keys.up.sql

@@ -0,0 +1,7 @@
+CREATE TABLE node_api_keys (
+    id SERIAL PRIMARY KEY,
+    key_name VARCHAR(100),
+    key_value VARCHAR(64) UNIQUE NOT NULL,
+    is_active BOOLEAN DEFAULT true,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);