Phase 1: Convention Update (THE SPEC)
Goal: Define the canonical note_type enum, status values per type, revised tag taxonomy, and README convention. This is the spec everything else builds on.
Owner: Main session (docs only)
Status: COMPLETE
Delivered: Updated
note-conventions with canonical note_type enum (10 values — bug merged into issue), status-per-type table, revised tag taxonomy (21 type tags + 9 lifecycle tags + 4 scope tags retiring, 13+ topic tags kept), README convention. Marked tagging-conventions deprecated.