Add bb document inspection commands

[codeforester]

Summary

• Add bb documents list for compact read-only v2 document inventory.
• Add bb documents show DOCUMENT_ID for document and canonical object details.
• Keep document inspection parser-free/inference-free and keep SQL behind DAO/service helpers.
• Update README, changelog, and AI context.

Validation

• uv run pytest tests/test_bb_cli.py tests/test_bb_documents_cli.py tests/test_bb_storage.py tests/test_bb_foundation.py tests/test_packaging.py -q
• ./tests/validate.sh
• git diff --check
• git diff --cached --check

Closes #134