Fill merch.json (Store A) + merge PR #153

[WalksWithASwagger]

Context

Punk Rock AI /merch (PR #153) ships with placeholders + fallback. To go live, fill the Store-A config. Epic: WalksWithASwagger/kk-kb#2071.

Scope (human — config + merge)

• Edit site/data/merch.json: set store.domain, store.storefrontToken, and each product's productId (punk-rock collection).
• Merge PR Add Punk Rock AI merch shop (Shopify Buy Buttons) #153.

Acceptance Criteria

• merch.json populated with the Krug store domain + Storefront token + product IDs.
• PR Add Punk Rock AI merch shop (Shopify Buy Buttons) #153 merged; /merch renders live Buy Buttons.

Dependencies

• Needs Store A (kk-kb#2072) + Store A product IDs (kk-kb#2075).

[WalksWithASwagger]

Roadmap hygiene note (2026-06-12): intentionally leaving this issue without a milestone because this repository currently has no milestones configured. Keeping it tracked as needs-human until Store A credentials/product IDs and PR #153 disposition are available.