Adds Phase A data model deltas to documents/templates and the new
document_watchers table. Introduces createFromWizard/createFromUpload
stubs, getDocumentDetail aggregator, cancelDocument flow, signed-doc
email composer, reservation agreement context, and notifyDocumentEvent
fan-out. Validator update accepts new template formats with html-only
bodyHtml requirement. EOI cadence backfilled to 1 day to preserve
current effective behaviour.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>