fix: License key format, login populates license, case-insensitive email

- admin.service.ts: createLicense() now uses CORR-XXXX-XXXX-XXXX format
  instead of raw hex hash
- admin.service.ts: getLicenses() flattens owner_email in response to
  match frontend expected shape
- auth.service.ts: Login/register responses now include full license
  object so frontend can populate auth store
- auth.service.ts: Email lookups are case-insensitive (LOWER()) to
  prevent duplicate accounts from case variations
- LoginView/RegisterView: Call setLicense() after setAuth()
- AdminLicenses: Handle null expires_at (was showing Dec 31, 1969),
  fix nullable types, fix query param name (per_page → limit)

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

frontend/src/views/auth/LoginView.vue

@@ -39,6 +39,9 @@ async function handleLogin() {
     }
 
     authStore.setAuth(response)
+    if (response.license) {
+      authStore.setLicense(response.license)
+    }
     router.push('/')
   } catch (err: unknown) {
     if (err instanceof Error) {
@@ -68,6 +71,9 @@ async function handleTotpVerify() {
     })
 
     authStore.setAuth(response)
+    if (response.license) {
+      authStore.setLicense(response.license)
+    }
     router.push('/')
   } catch (err: unknown) {
     totpCode.value = ''