refactor(ingest): remove internal cve syncer

[simonjcarr]

Summary

• remove CT Ops ingest's internal vulnerability feed syncer, host matcher scheduler, and deleted package
• drop legacy ingest vulnerability config/env documentation now owned by CT-CVE
• mark Phase 10 in progress with the completed ingest-removal slice

Validation

• go test ./...
• pnpm --dir apps/web type-check
• pnpm --dir apps/web test:unit
• git diff --check