Add recurring transactions with monthly confirmation flow

New "Récurrences" section lets users define recurring depense/epargne
models (name, category, default amount, day of month). Nothing is
created automatically: from the day a recurrence is due, it appears
as a pending proposal in Suivi (desktop + mobile) with an editable
amount, so variable bills (electricity, etc.) can be adjusted before
confirming. Dismissing a proposal skips it for the current month
without creating a transaction, and it reappears the following month.

- recurring_transactions table (household/category scoped, active flag,
  last_generated_year/month to prevent duplicate generation)
- transactions.recurring_transaction_id nullable FK to trace origin
- RecurringTransactionPolicy mirrors CategoryPolicy tenant scoping
- 10 new Pest tests covering CRUD, tenant isolation, and the
  pending/confirm/dismiss lifecycle across month boundaries (travelTo)

58/58 tests pass, Pint clean, verified end-to-end against production
data (test recurrence created and cleaned up).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/Models/Transaction.php

@@ -9,7 +9,7 @@ use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
 class Transaction extends Model
 {
-    protected $fillable = ['household_id', 'category_id', 'user_id', 'date', 'date_effective', 'amount', 'details'];
+    protected $fillable = ['household_id', 'category_id', 'recurring_transaction_id', 'user_id', 'date', 'date_effective', 'amount', 'details'];
 
     protected function casts(): array
     {