Add SandBase Harness - #46

I found missing media metadata and/or repo-managed submitter metadata that should be written back to the PR branch. I can't push directly to forked PR branches, but you can generate the same changes locally with:

git fetch 'https://github.com/bradvin/agentfirst.directory.git' '6cf84c70a4b3a1d6977e5933513e9cfa3949eb00'
git worktree add --detach '../agentfirst-base-46' FETCH_HEAD
npm run sync:tool-submitters -- --base-root-dir '../agentfirst-base-46' --submitted-by 'liyangbing' --slug 'sandbase-harness'
npm run enrich:tool-assets -- --write --slug 'sandbase-harness'
git worktree remove '../agentfirst-base-46'

Then commit the updated files to this PR branch.

Updated the fork branch with the requested generated metadata: tool-submitters.json, logoUrl, and ogImageUrl. The Enrich Tool Assets check now passes; local content tests and required-submitters validation also pass. Ready for maintainer review.

Rechecked the repository-maintained metadata instructions on the current PR branch.

• sync:tool-submitters --base-root-dir ... --submitted-by liyangbing --slug sandbase-harness completed with metadataChanged=0.
• enrich:tool-assets --write --slug sandbase-harness completed with logoUrl and ogImageUrl already present and changed=0.
• The branch already contains commit cf412e0 (Auto-fill tool media and submitter metadata), with tool-submitters.json mapping sandbase-harness to liyangbing and the tool page containing both media URLs.

No additional generated diff is required, and git diff --check passes.

@liyangbing pls change classification from agent-enabling to agent-native.

The current policy defines agent-native for products where agents are a core runtime or entity. SandBase Harness is explicitly an AI agent runtime: users create/import agents, attach tools and memory, start persistent agent sessions, and inspect their execution. That matches agent-native directly. agent-enabling is used for supporting infrastructure such as generic sandboxes, testing, or memory services.

Evidence: SandBase repository and usage guide.