fix: require open drawer to complete transactions, fix product price field

- Backend enforces open drawer at location before completing any transaction
- Frontend disables payment buttons when drawer is closed with warning message
- Fix product price field name (price, not sellingPrice) in POS API types
- Fix seed UUIDs to use valid UUID v4 format (version nibble must be 1-8)
- Fix Vite allowedHosts for dev.lunarfront.tech access
- Add e2e test for drawer enforcement (39 POS tests now pass)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/backend/api-tests/suites/pos.ts

@@ -273,6 +273,36 @@ suite('POS', { tags: ['pos'] }, (t) => {
 
   // ─── Complete Transaction ──────────────────────────────────────────────────
 
+  t.test('rejects completing transaction without open drawer', { tags: ['transactions', 'complete', 'validation', 'drawer'] }, async () => {
+    // Ensure no drawer is open at LOCATION_ID
+    const current = await t.api.get('/v1/drawer/current', { locationId: LOCATION_ID })
+    if (current.status === 200 && current.data.id) {
+      await t.api.post(`/v1/drawer/${current.data.id}/close`, { closingBalance: 0 })
+    }
+
+    const txn = await t.api.post('/v1/transactions', { transactionType: 'sale', locationId: LOCATION_ID })
+    await t.api.post(`/v1/transactions/${txn.data.id}/line-items`, {
+      description: 'No Drawer Item',
+      qty: 1,
+      unitPrice: 10,
+    })
+
+    const res = await t.api.post(`/v1/transactions/${txn.data.id}/complete`, {
+      paymentMethod: 'cash',
+      amountTendered: 20,
+    })
+    t.assert.status(res, 400)
+
+    // Void to clean up
+    await t.api.post(`/v1/transactions/${txn.data.id}/void`)
+  })
+
+  // Open a drawer for the remaining complete tests
+  t.test('opens drawer for complete tests', { tags: ['transactions', 'complete', 'setup'] }, async () => {
+    const res = await t.api.post('/v1/drawer/open', { locationId: LOCATION_ID, openingBalance: 200 })
+    t.assert.status(res, 201)
+  })
+
   t.test('completes a cash transaction with change', { tags: ['transactions', 'complete', 'cash'] }, async () => {
     const txn = await t.api.post('/v1/transactions', { transactionType: 'sale', locationId: LOCATION_ID })
     await t.api.post(`/v1/transactions/${txn.data.id}/line-items`, {
@@ -427,6 +457,18 @@ suite('POS', { tags: ['pos'] }, (t) => {
 
   // ─── Cash Rounding ─────────────────────────────────────────────────────────
 
+  // Close the LOCATION_ID drawer and open one at ROUNDING_LOCATION_ID
+  t.test('setup drawer for rounding tests', { tags: ['transactions', 'rounding', 'setup'] }, async () => {
+    // Close drawer at LOCATION_ID
+    const current = await t.api.get('/v1/drawer/current', { locationId: LOCATION_ID })
+    if (current.status === 200 && current.data.id) {
+      await t.api.post(`/v1/drawer/${current.data.id}/close`, { closingBalance: 200 })
+    }
+    // Open drawer at ROUNDING_LOCATION_ID
+    const res = await t.api.post('/v1/drawer/open', { locationId: ROUNDING_LOCATION_ID, openingBalance: 200 })
+    t.assert.status(res, 201)
+  })
+
   t.test('cash rounding adjusts total to nearest nickel', { tags: ['transactions', 'rounding'] }, async () => {
     // Create transaction at the rounding-enabled location
     const txn = await t.api.post('/v1/transactions', {
@@ -484,6 +526,10 @@ suite('POS', { tags: ['pos'] }, (t) => {
   })
 
   t.test('no rounding at non-rounding location', { tags: ['transactions', 'rounding'] }, async () => {
+    // Open drawer at LOCATION_ID for this test
+    const drawer = await t.api.post('/v1/drawer/open', { locationId: LOCATION_ID, openingBalance: 100 })
+    t.assert.status(drawer, 201)
+
     const txn = await t.api.post('/v1/transactions', {
       transactionType: 'sale',
       locationId: LOCATION_ID,
@@ -500,6 +546,17 @@ suite('POS', { tags: ['pos'] }, (t) => {
     })
     t.assert.status(res, 200)
     t.assert.equal(parseFloat(res.data.roundingAdjustment), 0)
+
+    // Cleanup
+    await t.api.post(`/v1/drawer/${drawer.data.id}/close`, { closingBalance: 100 })
+  })
+
+  // Close rounding location drawer
+  t.test('cleanup rounding drawer', { tags: ['transactions', 'rounding', 'setup'] }, async () => {
+    const current = await t.api.get('/v1/drawer/current', { locationId: ROUNDING_LOCATION_ID })
+    if (current.status === 200 && current.data.id) {
+      await t.api.post(`/v1/drawer/${current.data.id}/close`, { closingBalance: 200 })
+    }
   })
 
   // ─── Full POS Flow ────────────────────────────────────────────────────────