Add StellarTools ecosystem skill card

[princeajuzie7]

⁠ Stripe-level payment infrastructure for Stellar. Accept crypto and fiat payments with hosted checkouts, Soroban-powered subscriptions with flexible billing periods, customer portals, and normalized webhooks. Includes WooCommerce and Shopify adapters, an apps marketplace, and an MCP server for agent-driven payment management. ⁠

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[kaankacar]

Thanks for adding StellarTools to the catalog, Prince — this is a genuinely thorough submission. I went through the SKILL.md against the actual @stellartools/core source (not just the marketing docs) and everything checks out:

• Config really is just a single api_key field, and it does encode testnet vs. mainnet — confirmed in packages/stellartools/src/index.ts.
• Every docs-vs-SDK drift note you called out is real: st.checkout (singular) in the docs samples vs. st.checkouts (plural) on the actual client, amount/asset_code in the docs vs. amount_cents/currency_code in the schema, monthly/yearly in the docs vs. the short-form month/year the SDK enum actually takes, the metered product type mentioned on the TypeScript SDK doc page that isn't in productTypeEnum (only one_time/subscription exist), the customers.access.verify method shown in the Products doc that doesn't exist on CustomerApi, and subscription.renewed mentioned in the docs that isn't in WEBHOOK_EVENT_TYPES.
• Webhook verification hard-rejects on a bad or missing signature (throws SignatureVerificationError) rather than logging and continuing — good practice, and accurately described.
• I hit the live MCP server's tools/list directly and it matches your breakdown exactly: checkouts get read/updated/deleted but not created, subscriptions only expose get_subscriptions (list by customer), there are no webhook-management tools at all, and there's no currency/asset tool in the wired list — consistent with your note that those are declared but never wired in.
• docs.stellartools.dev, the MCP endpoints, and the linked SKILL.md URL all resolve, and the API key is explicitly documented as server-side only, so no key-handling or auto-execution red flags here.

Approving and merging.

[kaankacar]

Looks solid — merging.