feat: Add comprehensive database schema migrations for all platform tables

- Add subscribers table with IMSI, MSISDN, authentication keys, and eSIM profile fields
- Add service_plans table for data/voice/SMS limits and QoS parameters (ARPA, AMBR)
- Add sessions table for tracking PDU sessions with QoS and usage metrics
- Add usage_records table for billing and charging data
- Add users table with role-based access control fields
- Add roles, permissions, and role_permissions junction table for RBAC
- Add auth

migrations/00007_init_users.sql

@@ -0,0 +1,26 @@
+-- +goose Up
+-- Create users table
+CREATE TABLE IF NOT EXISTS users (
+    id         SERIAL PRIMARY KEY,
+    username   TEXT NOT NULL UNIQUE,
+    email      TEXT NOT NULL UNIQUE,
+    password   TEXT NOT NULL,
+    first_name TEXT NOT NULL,
+    last_name  TEXT NOT NULL,
+    role       TEXT NOT NULL DEFAULT 'viewer',
+    is_active  BOOLEAN NOT NULL DEFAULT true,
+    last_login TIMESTAMPTZ,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    deleted_at  TIMESTAMPTZ
+);
+
+-- Create indexes
+CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
+CREATE INDEX IF NOT EXISTS idx_users_email ON users(email);
+CREATE INDEX IF NOT EXISTS idx_users_role ON users(role);
+CREATE INDEX IF NOT EXISTS idx_users_deleted_at ON users(deleted_at);
+
+-- +goose Down
+-- Drop users table
+DROP TABLE IF EXISTS users CASCADE;