fix(payment): resolve PR audit issues

- Add payment navigation to AppSidebar (user orders + admin payment menu group with collapse)
- Add 5 missing nav i18n keys (myOrders, orderManagement, paymentDashboard, paymentConfig, paymentPlans)
- Renumber payment migrations 090-100 → 092-102 to avoid conflict with upstream 090/091
- Remove non-payment sora_client_enabled change, restore upstream purchase_subscription fields
- Remove extra 'data' from SettingsTab type union

backend/migrations/095_subscription_plans.sql

@@ -0,0 +1,18 @@
+CREATE TABLE IF NOT EXISTS subscription_plans (
+    id BIGSERIAL PRIMARY KEY,
+    group_id BIGINT NOT NULL,
+    name VARCHAR(100) NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    price DECIMAL(20,2) NOT NULL,
+    original_price DECIMAL(20,2),
+    validity_days INT NOT NULL DEFAULT 30,
+    validity_unit VARCHAR(10) NOT NULL DEFAULT 'day',
+    features TEXT NOT NULL DEFAULT '',
+    product_name VARCHAR(100) NOT NULL DEFAULT '',
+    for_sale BOOLEAN NOT NULL DEFAULT TRUE,
+    sort_order INT NOT NULL DEFAULT 0,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+CREATE INDEX IF NOT EXISTS idx_subscription_plans_group_id ON subscription_plans(group_id);
+CREATE INDEX IF NOT EXISTS idx_subscription_plans_for_sale ON subscription_plans(for_sale);