Mirrors the decnet.intel layout (base + factory + lazy concrete
imports). Defines:
- CanaryArtifact / CanaryContext dataclasses + the generator and
instrumenter ABCs they share
- factory dispatch for generators (git_config/env_file/ssh_key/
aws_creds/honeydoc) and instrumenters (docx/xlsx/pdf/html/image/
plain/passthrough), plus pick_instrumenter_for_mime() for MIME-driven
dispatch on operator uploads
- persona-aware default placement paths (Linux vs. Windows-shaped)
and absolute-path validation that the API will use to validate
operator-supplied placement_path values
- on-disk blob store: sha256-keyed two-level fan-out, idempotent
writes, refcount-aware unlink (the DB row is the source of truth)
Also covers prior commits' tests (bus topics, models, repo CRUD)
under tests/canary/. 79 tests, all pass.
