feat(materials): add CHAINLOOP_AI_SECURITY_CONTEXT material type
Merged
MA
2mo ago+5008+5008+0123456789012345678901234567890123456789-38-38-01234567890123456789
Closes PFM-7010
Summary
Adds a first-party material type for the security context artifact: recurring vulnerability fingerprints mined from a repository's fix history, the attack surfaces they share, ranked risks, and byte-verifiable evidence anchors backing each claim.
The payload is validated against an embedded, versioned JSON schema. The Chainloop evidence envelope is asserted in the crafter, matching the other first-party material types whose schemas are payload-rooted.