feat: add canonical publication and Web delivery pipeline

[CylenLC]

Summary

Implements the DailyInfo backend side of issue #7: turn pipeline output into validated canonical publications and provide an independent Web delivery path.

The frontend interface is maintained in the separate repository CylenLC/dailyinfo-web. This PR does not modify that repository.

What changed

• Added canonical Publication v1 models for items, briefings, and bundles.
• Added deterministic identity, serialization, semantic hashing, validation, and atomic local persistence.
• Integrated structured pipeline output into the canonical publication store while preserving existing briefing and Discord behavior.
• Added delivery-state separation and publisher abstraction.
• Added Web publishing from canonical publications to the configured dailyinfo-web checkout.
• Added CLI controls for date- and category-scoped publication delivery.
• Added unit, integrity, determinism, store, and pipeline regression coverage.

Scope boundaries

• No database or HTTP API.
• No direct Web repository changes in this PR.
• The Web UI remains in CylenLC/dailyinfo-web.
• Discord delivery remains a separate sink.

Verification

• pytest -q — 285 passed
• git diff --cached --check — passed

Closes #7