SAP OM: org units, jobs, positions, and a derived reporting line

The org structure was three fixed tables — divisions -> departments ->
teams — with people hanging directly off them and a hand-maintained
manager_id. The depth was therefore wired into the schema: an Abteilungsleitung
could not exist without a migration, and a team directly under a Bereich not
at all. That is what this replaces.

The SAP OM object types, one table each:

  O  org_units             recursive over parent_id
  C  jobs                  catalogue, so many positions can share a job
  S  om_positions          belongs to exactly one org unit
  P  employees             existing table
  A012 om_positions.is_chief          "ist Leiter von"
  A008 position_assignments           "Inhaber ist", time-dependent

Two consequences worth stating, because they are the point of the exercise:

- GF/Bereich/Abteilung/Team are now a label (unit_type), not a structure.
  Adding a fifth level, or hanging a team straight off a Bereich, becomes a
  data question rather than a migration.
- Nobody hangs off an org unit any more: person -> position -> unit. A
  vacancy stops being its own concept — it is a position with no current
  assignment.

The reporting line is derived rather than stored: an ordinary position
reports to the chief of its own unit, a chief to the chief of the parent
unit, and if that chief is vacant or on a long-term absence it keeps
climbing. An unfilled Abteilungsleitung therefore needs no special case —
it is simply skipped. Both ids come back, formal and acting, so the UI can
show a stand-in as a stand-in instead of passing it off as the real manager.

The rule exists twice, as om_reporting_lines() in SQL and
resolveReportingLines() in TypeScript, because the as-of chart computes it
per date in the app and a round trip per date change would buy nothing. Two
copies drift silently — the org chart would just show a different manager
than the export — so an integration test runs both over the whole roster and
requires identical answers, plus that every line terminates at the top.

Unit tests cover the rule itself: unfilled levels, several absent levels in
a row, nobody above, a chief who also leads the parent unit, and a cycle in
parent_id, which is an ordinary column an import could get wrong.

Additive so far. The old tables still stand and the app still reads them;
the cut-over follows.

lib/supabase/types.ts

@@ -18,6 +18,8 @@ export type NoteCategory = "Allgemein" | "Vertraulich" | "Personalgespräch" | "
 // union (not a string literal) so a future hr_admin/hr_user split, if ever
 // technically required, is a type-level addition, not a rewrite.
 export type ProfileRole = "hr";
+/** Etikett einer Organisationseinheit; die Struktur steckt in parent_id. */
+export type OrgUnitType = "Gesellschaft" | "Bereich" | "Abteilung" | "Team";
 export type HistoryEventType =
   | "Eintritt"
   | "Beförderung"
@@ -395,6 +397,86 @@ export type Database = {
       };
       // Written exclusively by trg_track_employee_assignment; RLS grants HR
       // read access only, hence no Insert/Update shapes worth modelling.
+      // ── SAP-OM-Modell ──────────────────────────────────────────
+      // O: rekursiv über parent_id, unit_type ist nur ein Etikett.
+      org_units: NoRelationships & {
+        Row: {
+          id: string;
+          org_number: string;
+          name: string;
+          parent_id: string | null;
+          unit_type: OrgUnitType;
+          valid_from: string;
+          valid_to: string | null;
+          created_at: string;
+        };
+        Insert: {
+          id?: string;
+          org_number: string;
+          name: string;
+          parent_id?: string | null;
+          unit_type: OrgUnitType;
+          valid_from?: string;
+          valid_to?: string | null;
+          created_at?: string;
+        };
+        Update: Partial<Database["public"]["Tables"]["org_units"]["Insert"]>;
+      };
+      // C: Katalog der Tätigkeiten.
+      jobs: NoRelationships & {
+        Row: { id: string; code: string; title: string; created_at: string };
+        Insert: { id?: string; code: string; title: string; created_at?: string };
+        Update: Partial<Database["public"]["Tables"]["jobs"]["Insert"]>;
+      };
+      // S: Planstelle. Heisst om_positions, weil `positions` noch die alte
+      // Tabelle für offene Stellen ist, bis der Umstieg abgeschlossen ist.
+      om_positions: {
+        Row: {
+          id: string;
+          position_number: string;
+          org_unit_id: string;
+          job_id: string;
+          is_chief: boolean;
+          valid_from: string;
+          valid_to: string | null;
+          created_at: string;
+        };
+        Insert: {
+          id?: string;
+          position_number: string;
+          org_unit_id: string;
+          job_id: string;
+          is_chief?: boolean;
+          valid_from?: string;
+          valid_to?: string | null;
+          created_at?: string;
+        };
+        Update: Partial<Database["public"]["Tables"]["om_positions"]["Insert"]>;
+        Relationships: [];
+      };
+      // A008: Person besetzt Planstelle, zeitabhängig.
+      position_assignments: {
+        Row: {
+          id: string;
+          position_id: string;
+          employee_id: string;
+          valid_from: string;
+          valid_to: string | null;
+          created_at: string;
+        };
+        Insert: {
+          id?: string;
+          position_id: string;
+          employee_id: string;
+          valid_from: string;
+          valid_to?: string | null;
+          created_at?: string;
+        };
+        Update: Partial<Database["public"]["Tables"]["position_assignments"]["Insert"]>;
+        // Einbettung auf die Planstelle, damit die Berichtslinie in einer
+        // Abfrage geladen werden kann.
+        Relationships: [{ foreignKeyName: "position_assignments_position_id_fkey"; columns: ["position_id"]; referencedRelation: "om_positions"; referencedColumns: ["id"] }];
+      };
       employee_assignments: NoRelationships & {
         Row: {
           id: string;
@@ -435,6 +517,17 @@ export type Database = {
       apply_reorg: { Args: { payload: Record<string, unknown> }; Returns: string };
       undo_reorg: { Args: { payload: Record<string, unknown> }; Returns: void };
       apply_due_pending_changes: { Args: Record<string, never>; Returns: number };
+      om_reporting_lines: {
+        Args: { p_as_of?: string };
+        Returns: {
+          employee_id: string;
+          position_id: string;
+          org_unit_id: string;
+          is_chief: boolean;
+          formal_manager_id: string | null;
+          acting_manager_id: string | null;
+        }[];
+      };
     };
   };
 };