feat(site): add mnemospark to x402 ecosystem

[pawlsclick]

Description

Add mnemospark to the public Ecosystem directory so builders can discover the OpenClaw + x402 / USDC on Base storage API and plugin.

• New partner entry: typescript/site/app/ecosystem/partners-data/mnemospark/metadata.json (name mnemospark, category Services/Endpoints, link https://mnemospark.ai).
• Logo asset: typescript/site/public/logos/mnemospark.svg (served as /logos/mnemospark.svg per existing ecosystem conventions).

No protocol, SDK, or facilitator code changes.

Tests

• Confirmed the two files are present and metadata.json matches the shape used by other partners-data/*/metadata.json entries.
• Verified the commit is SSH-signed locally (git log -1 --show-signature → good git signature).
• Not run: pnpm test / full monorepo test matrix — change is static site assets only; happy to run a specific site or typescript check if maintainers want it in CI.

Checklist

• I have formatted and linted my code (static JSON + SVG only; no TS/Go/Python source touched)
• All new and existing tests pass (same reason as above)
• My commits are signed (required for merge) -- you may need to rebase if you initially pushed unsigned commits
• I added a changelog fragment for user-facing changes (docs-only changes can skip) — skipped: ecosystem listing only; no user-facing change to published @x402/* packages or runtime behavior.

[vercel]

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