Remove product-specific runtime bundle metadata

[chubes4]

Summary

• Remove the Data Machine-specific runtime bundle config key from the generic runtime bundle importer.
• Populate generic runtime bundle provenance from top-level bundle_slug and bundle_version instead.
• Keep Agents API core-safe: no Homeboy/Data Machine/Codebox production vocabulary and no storage/table changes.

Verification

• php tests/runtime-agent-bundle-importer-smoke.php
• php tests/bootstrap-smoke.php
• php -l src/Registry/register-agent-runtime-bundle-importer.php
• git diff --check

Notes

• Local composer phpstan could not run in this skip-bootstrap worktree because phpstan is not installed; CI should run the full composer checks.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Auditing boundary vocabulary, drafting the metadata cleanup, and running local verification; Chris remains responsible for review and merge.