feat(w10c): migrate remaining 7 non-core agents to substrate_role
All 12 kit-shipped agents now declare substrate_role:
- 7 read-only: kei-cost-guardian, kei-ml-researcher, kei-researcher,
kei-critic, kei-architect, kei-security-auditor, kei-validator
- 5 edit-local: kei-modal-runner, kei-fal-ai-runner, kei-infra-implementer,
kei-ml-implementer, kei-code-implementer
Assembler regenerated 7 new .md files with # AGENT SUBSTRATE — role header.
docs/AGENT-ROLES.md: 12-row table + maintenance note.
substrate_integration.sh: migrated floor 5 → 12.
assembler tests (non_migrated) adjusted to strip substrate_role from
temp kit copy since all shipped manifests are now migrated.
cargo test agent-assembler: 47/47 (was 40, +7 regenerate tests).
cargo check --workspace: PASS.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>