Implement opal-task Phase 1: Database foundation

- Add SQLite database with schema for tasks, tags, and working_set
- Implement config management with Viper (opal.yml)
- Create Task struct with proper types (*time.Time, Priority int)
- Add database migration system
- Implement recurrence pattern parsing (1d, 1w, 1m, 1y)
- Setup project structure with cmd/ and internal/engine/
- Add dependencies: sqlite3, uuid, cobra, viper, color

opal-task/main.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"git.jnss.me/joakim/opal/internal/engine"
+)
+
+func main() {
+	// Initialize database
+	if err := engine.InitDB(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error initializing database: %v\n", err)
+		os.Exit(1)
+	}
+	defer engine.CloseDB()
+
+	// Load config
+	if _, err := engine.LoadConfig(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Println("Opal task manager initialized successfully!")
+	fmt.Println("Database and configuration ready.")
+}