fix: address code review findings from story #01

- Makefile: -include .env (soft) so fresh clone doesn't hard-fail
- main.go: replace log.Fatalf-in-goroutine with error channel; startup
  failures now reach main goroutine so defer pool.Close() always runs
- main.go: context.WithTimeout(30s) on database.Connect to fail fast
  instead of hanging indefinitely on unreachable Postgres
- router.go: store pool on Echo context via middleware so future story
  handlers can retrieve it with c.Get("pool")
- config.go: require DATABASE_URL explicitly (log.Fatal if missing)
  instead of falling back to hardcoded credentials
- HelloWorld.test.ts: URL-aware fetch stub + afterEach restoreAllMocks;
  add flushPromises test verifying backend status renders

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/views/HelloWorld.test.ts

@@ -1,23 +1,37 @@
-import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { mount } from '@vue/test-utils'
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
+import { mount, flushPromises } from '@vue/test-utils'
 import { createPinia } from 'pinia'
 import HelloWorld from './HelloWorld.vue'
 
-// Stub fetch so the component's onMounted health call doesn't hit the network.
+// Stub fetch; URL-aware so future tests can extend without cross-contamination.
+const fetchMock = vi.fn((url: string) => {
+  if (url === '/api/v1/health') {
+    return Promise.resolve({ ok: true, json: async () => ({ status: 'ok' }) })
+  }
+  return Promise.reject(new Error(`Unexpected fetch: ${url}`))
+})
+
 beforeEach(() => {
-  vi.stubGlobal('fetch', vi.fn().mockResolvedValue({
-    ok: true,
-    json: async () => ({ status: 'ok' }),
-  }))
+  vi.stubGlobal('fetch', fetchMock)
+})
+
+afterEach(() => {
+  vi.restoreAllMocks()
 })
 
 describe('HelloWorld', () => {
   it('renders the OSDB greeting', async () => {
     const wrapper = mount(HelloWorld, {
-      global: {
-        plugins: [createPinia()],
-      },
+      global: { plugins: [createPinia()] },
     })
     expect(wrapper.text()).toContain('Hello, OSDB!')
   })
+
+  it('displays backend status after health check resolves', async () => {
+    const wrapper = mount(HelloWorld, {
+      global: { plugins: [createPinia()] },
+    })
+    await flushPromises()
+    expect(wrapper.text()).toContain('ok')
+  })
 })