fix(cookbook): quote step values in legacy-customer-account-flow recipe

YAML parses bare `step: 1` as a JavaScript number, but the Zod schema
(StepSchema.step) expects z.string().regex(/^\d+(?:\.\d+)?$/). This
type mismatch caused all 6 legacy-customer-account-flow e2e tests to
fail at fixture generation time with:
  RecipeSchema: Invalid input: expected string, received number

Quoting the values (`step: "1"`) forces YAML to preserve them as strings,
matching what the schema requires.

Author: itsjustriley

cookbook/recipes/legacy-customer-account-flow/recipe.yaml

@@ -46,108 +46,108 @@ ingredients:
 deletedFiles: []
 steps:
   - type: PATCH
-    step: 1
+    step: "1"
     name: Document legacy customer accounts in the README
     description: Update the README file to document the legacy customer account flow.
     diffs:
       - file: README.md
         patchFile: README.md.a0354d.patch
   - type: PATCH
-    step: 2
+    step: "2"
     name: Add account link to header navigation
     description: Add an account link to the header navigation.
     diffs:
       - file: app/components/Header.tsx
         patchFile: Header.tsx.994c25.patch
   - type: NEW_FILE
-    step: 3
+    step: "3"
     name: Create account activation flow
     description: Add an account activation route for email verification.
     ingredients:
       - path: templates/skeleton/app/routes/account_.activate.$id.$activationToken.tsx
   - type: PATCH
-    step: 4
+    step: "4"
     name: Update PageLayout for legacy auth
     description: Update PageLayout to handle account routes.
     diffs:
       - file: app/components/PageLayout.tsx
         patchFile: PageLayout.tsx.145dab.patch
   - type: NEW_FILE
-    step: 5
+    step: "5"
     name: Build password recovery flow
     description: Add a password recovery form.
     ingredients:
       - path: templates/skeleton/app/routes/account_.recover.tsx
   - type: PATCH
-    step: 6
+    step: "6"
     name: Validate customer access tokens
     description: Add customer access token validation to the root loader.
     diffs:
       - file: app/root.tsx
         patchFile: root.tsx.8c60e9.patch
   - type: NEW_FILE
-    step: 7
+    step: "7"
     name: Create customer registration flow
     description: Add a customer registration form.
     ingredients:
       - path: templates/skeleton/app/routes/account_.register.tsx
   - type: PATCH
-    step: 8
+    step: "8"
     name: Handle unauthenticated account routes
     description: Convert the catch-all route to use Storefront API authentication.
     diffs:
       - file: app/routes/account.$.tsx
         patchFile: account.$.tsx.5ed838.patch
   - type: NEW_FILE
-    step: 9
+    step: "9"
     name: Build password reset flow
     description: Add a password reset form with token validation.
     ingredients:
       - path: templates/skeleton/app/routes/account_.reset.$id.$resetToken.tsx
   - type: PATCH
-    step: 10
+    step: "10"
     name: Add address management
     description: Convert address management to use Storefront API mutations.
     diffs:
       - file: app/routes/account.addresses.tsx
         patchFile: account.addresses.tsx.f3bb60.patch
   - type: PATCH
-    step: 11
+    step: "11"
     name: Show order details
     description: Convert the order details page to use Storefront API queries.
     diffs:
       - file: app/routes/account.orders.$id.tsx
         patchFile: account.orders.$id.tsx.56d9c4.patch
   - type: PATCH
-    step: 12
+    step: "12"
     name: Display order history
     description: Convert the orders list to use the Storefront API with pagination.
     diffs:
       - file: app/routes/account.orders._index.tsx
         patchFile: account.orders._index.tsx.8942cc.patch
   - type: PATCH
-    step: 13
+    step: "13"
     name: Build customer profile page
     description: Convert the customer profile page to use Storefront API queries.
     diffs:
       - file: app/routes/account.profile.tsx
         patchFile: account.profile.tsx.8e4050.patch
   - type: PATCH
-    step: 14
+    step: "14"
     name: Update account layout for session auth
     description: Convert the account layout to use session-based authentication.
     diffs:
       - file: app/routes/account.tsx
         patchFile: account.tsx.30f6e3.patch
   - type: PATCH
-    step: 15
+    step: "15"
     name: Create login page
     description: Replace the Customer Account API login with the Storefront API form.
     diffs:
       - file: app/routes/account_.login.tsx
         patchFile: account_.login.tsx.d75928.patch
   - type: PATCH
-    step: 16
+    step: "16"
     name: Handle logout and session cleanup
     description: Replace the Customer Account API logout with a session cleanup.
     diffs: