Add "Transit" as a third classification dimension (alongside Type and State)

[Jenziner]

Problem

RWC currently classifies a Record along two axes: Type (what it is,
schema-bound) and State (draft/finalized, its maturity). Records
Management practice distinguishes a third, orthogonal axis: the direction
of a Record relative to the issuing institution — inherited from the classic
EVA principle (Eingang/Verarbeitung/Ausgang) and from ISO 15489 incoming/
outgoing correspondence practice.

This dimension is currently invisible in RWC, even though it is implicitly
present in the poc-fragestunde (the "Frage" Record is outgoing from Parliament,
the "Antwort" is outgoing from the Federal Council).

Proposal

Introduce Transit as a defined term and third classification dimension,
with three values:

• incoming — a Record created upon receipt of information from outside
  RecordWeb (e.g. a physiotherapist capturing a citizen-supplied X-ray as a
  new Record with external provenance).
• internal — a Record that remains within the issuing institution's own
  sphere throughout its lifecycle.
• outgoing — a Record (or a derived artifact thereof) that is deliberately
  transmitted to a party outside the issuing institution's sphere.

Proposed text (for insertion after Section 6.4, "States")

6.4a Transit: The Direction of a Record

Alongside Type and State, a Record carries a third, orthogonal
classification: its Transit. While Type describes what a Record is
and State describes its maturity, Transit describes its relationship to
the issuing institution's boundary.

A Record with Transit incoming is created upon receipt of information
originating outside RecordWeb — for example, a physiotherapist capturing
an X-ray image brought in by a patient as a new Record with explicit
external provenance. A Record with Transit outgoing is one whose content,
or a signed derivation thereof, is deliberately transmitted beyond the
issuing institution — for example, a finalized decision handed to its
addressee. A Record with Transit internal remains within the issuing
institution throughout its lifecycle.

Transit is metadata, not identity: it does not change a Record's DID, its
Type, or its State. It is declared once, at creation, based on the
circumstances of the Record's origin.

Open questions for CG discussion

• Does internal need a fourth value for inter-departmental transfer within
  the same institution but across organizational boundaries?
• Is Transit mandatory metadata or optional?