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/00003_init_subscribers.sql

@@ -0,0 +1,38 @@
+-- +goose Up
+-- Create subscribers table
+CREATE TABLE IF NOT EXISTS subscribers (
+    id            SERIAL PRIMARY KEY,
+    imsi          TEXT NOT NULL UNIQUE,
+    msisdn        TEXT UNIQUE,
+    imei          TEXT,
+    first_name    TEXT NOT NULL,
+    last_name     TEXT NOT NULL,
+    email         TEXT UNIQUE,
+    organization_id TEXT,
+    status        TEXT NOT NULL DEFAULT 'active',
+    plan_id       INTEGER,
+    balance       DOUBLE PRECISION NOT NULL DEFAULT 0,
+    auth_key      TEXT NOT NULL,
+    opc           TEXT NOT NULL,
+    serving_plmn_mcc TEXT NOT NULL,
+    serving_plmn_mnc TEXT NOT NULL,
+    euicc_id      TEXT,
+    profile_id    TEXT,
+    profile_status TEXT NOT NULL DEFAULT 'inactive',
+    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_subscribers_imsi ON subscribers(imsi);
+CREATE INDEX IF NOT EXISTS idx_subscribers_msisdn ON subscribers(msisdn);
+CREATE INDEX IF NOT EXISTS idx_subscribers_email ON subscribers(email);
+CREATE INDEX IF NOT EXISTS idx_subscribers_status ON subscribers(status);
+CREATE INDEX IF NOT EXISTS idx_subscribers_organization_id ON subscribers(organization_id);
+CREATE INDEX IF NOT EXISTS idx_subscribers_plan_id ON subscribers(plan_id);
+CREATE INDEX IF NOT EXISTS idx_subscribers_deleted_at ON subscribers(deleted_at);
+
+-- +goose Down
+-- Drop subscribers table
+DROP TABLE IF EXISTS subscribers CASCADE;