refactor: improve database initialization and news fetching structure

backend/app/schema.sql

@@ -0,0 +1,34 @@
+-- Database schema for Owly News Summariser
+
+-- News table to store articles
+CREATE TABLE IF NOT EXISTS news (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    title       TEXT NOT NULL,
+    description TEXT,
+    url         TEXT NOT NULL,
+    published   TIMESTAMP NOT NULL,
+    country     TEXT NOT NULL,
+    created_at  TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Index for faster queries on published date
+CREATE INDEX IF NOT EXISTS idx_news_published ON news(published);
+
+-- Feeds table to store RSS feed sources
+CREATE TABLE IF NOT EXISTS feeds (
+     id      INTEGER PRIMARY KEY,
+     country TEXT,
+     url     TEXT UNIQUE NOT NULL
+);
+
+-- Settings table for application configuration
+CREATE TABLE IF NOT EXISTS settings (
+    key TEXT PRIMARY KEY,
+    val TEXT NOT NULL
+);
+
+-- Meta table for application metadata
+CREATE TABLE IF NOT EXISTS meta (
+    key TEXT PRIMARY KEY,
+    val TEXT NOT NULL
+);