fix: downgrade missing extension env vars to warning, add error boundaries and cron auth fixes

- Change missing extension env vars from throw to log.warn (graceful degradation)
- Move initialized flag after all init steps complete
- Add error.tsx and loading.tsx for dashboard error boundaries
- Fix cron route auth header checks
- Add ensureInitialized() to journal entry reverse and invoice mark-paid/sent routes

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

lib/bookkeeping/engine.ts

@@ -394,14 +394,23 @@ export async function reverseEntry(
     throw new Error(`Failed to post reversal entry: ${postError.message}`)
   }
 
-  // Mark original as reversed with reversed_by_id link
-  await supabase
+  // Mark original as reversed with reversed_by_id link (CAS guard: only if still 'posted')
+  const { data: updatedOriginal, error: casError } = await supabase
     .from('journal_entries')
     .update({
       status: 'reversed',
       reversed_by_id: reversalEntry.id,
     })
     .eq('id', entryId)
+    .eq('status', 'posted')
+    .select('id')
+
+  if (casError || !updatedOriginal || updatedOriginal.length === 0) {
+    // Another concurrent reversal already changed the status — roll back our reversal
+    await supabase.from('journal_entry_lines').delete().eq('journal_entry_id', reversalEntry.id)
+    await supabase.from('journal_entries').delete().eq('id', reversalEntry.id)
+    throw new Error('Entry was already reversed by a concurrent operation')
+  }
 
   // Fetch complete reversal entry with lines
   const { data: completeEntry } = await supabase

lib/init.ts

@@ -46,7 +46,7 @@ function validateEnvironment(): void {
   }
 
   if (missingExt.length > 0) {
-    throw new Error(`Missing required extension environment variables: ${missingExt.join(', ')}`)
+    log.warn(`Missing extension environment variables (extensions needing them may not work): ${missingExt.join(', ')}`)
   }
 
   for (const v of OPTIONAL_VARS) {
@@ -64,10 +64,11 @@ function validateEnvironment(): void {
  */
 export function ensureInitialized(): void {
   if (initialized) return
-  initialized = true
 
   validateEnvironment()
   setContextFactory(createExtensionContext)
   registerSupplierInvoiceHandler()
   loadExtensions()
+
+  initialized = true
 }