⚡ Optimize collection products grouping in Navbar

[AJFrio]

💡 What:
Replaced an O(N*M) nested filtering loop with an O(N+M) dictionary lookup using reduce. Specifically, grouped all products by collectionId into a dictionary first, and then populated the products array inside collectionsData.map() by looking up the dictionary.

🎯 Why:
The previous implementation filtered the entire products array for each collection being mapped over. As the number of products and collections grows, this causes significant UI blocking and performance degradation on the client side when loading the storefront navigation.

📊 Measured Improvement:
Created a baseline benchmark using benchmarks/navbar-collections.js with 100 collections and 5000 products:

• Baseline Avg: 8.30 ms
• Optimized Avg: 0.40 ms
• Improvement: ~95% faster execution time for the grouping logic.

---

PR created automatically by Jules for task 1352758579920581065 started by @AJFrio

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: c1ab40636d

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Use a prototype-safe key map for collection grouping

The new grouping logic stores products in a plain object keyed by product.collectionId, but IDs come from API data and can collide with inherited keys like constructor or toString. In those cases if (!acc[id]) incorrectly treats the inherited function as an existing bucket and acc[id].push(...) throws, which breaks navbar rendering for affected stores; the previous filter-based version did not have this failure mode. Use Object.create(null) or a Map (or at least Object.hasOwn) for bucket lookups.

Useful? React with 👍 / 👎.