Comprehensive design doc for the replacement of flat paliad.akten with:
- paliad.mandanten (Clients as first-class table)
- paliad.projekte (single self-referential typed tree, ltree materialised
path, 5 project types: mandat/litigation/patent/verfahren/projekt)
- paliad.teams + paliad.team_mitglieder (Dezernate + project teams in one
table with kind-shape CHECK)
- paliad.projekt_mitglieder (hot-path junction replacing akten.collaborators)
Polymorphic FK strategy: single project_id FK on fristen/termine/dokumente/
parteien/akten_events/checklist_instances. Notizen keeps its 4-way polymorphic
shape (akte_id renamed to project_id).
Visibility model: tree-connected — seeing any node grants access to the whole
tree (ancestors + descendants). Office-scope stays at project level; Mandant-
level firm_wide_visible / collaborators override.
Migration plan: 6 phases, non-destructive. UUIDs preserved between akten and
projekte rows so child tables only need column renames, no data moves.
Opinionated: German naming throughout (mandanten, projekte, teams,
team_mitglieder, projekt_mitglieder); /akten URLs alias to /projekte
indefinitely; akten_events table name kept for continuity.
Deliverable: docs/design-data-model-v2.md (920 lines, 14 sections).
fabe32aa56