composition skeleton: L1 accounting domain + six L2 function-group packages

Step 2 of the vk-gramatvediba build (absorbs the planned Step 3 — the
enterprise index now references the domain, since the two are one
coherent unit).

- domains/gramatvediba/ — L1 domain package; includes the six FG packages
- processes/fg1..fg6/ — six L2 function-group packages (composition stubs;
  FG3 carries its sub-process inventory and is taken to executable depth
  in later steps)
- each package: uapf.yaml + metadata/ownership.yaml + metadata/lifecycle.yaml
  + README
- enterprise/enterprise.yaml now references the L1 domain

All 22 manifests and metadata files validate against the UAPF 2.2.0
schemas; all seven includes / enterprise references resolve.

processes/fg3/README.md

@@ -0,0 +1,22 @@
+# FG3 — Saistību un izdevumu uzskaite
+
+Function group 3 - accounting for liabilities and expenses: supplier data and contract management, receipt and processing of invoices and supporting documents, and business-trip and economic settlements.
+
+- **UAPF level:** L2 (function group)
+- **Package id:** `vk.gramatvediba.fg3`
+- **Source:** Valsts Kase *Grāmatvedības uzskaites procesu apraksts* — FG3 schema and process register.
+
+## Status
+
+Composition placeholder. FG3 is the function group taken to executable
+depth in this proof-of-concept. Its six sub-process packages and the FG3-1
+executable build are added in subsequent steps:
+
+| Sub-process | Title |
+|-------------|-------|
+| FG3-1 | Rēķina/kredītrēķina saņemšana par precēm/pakalpojumiem |
+| FG3-2 | Iepirkuma līguma darbības izbeigšana |
+| FG3-3 | Klienta datu pārvaldība |
+| FG3-4 | Saimnieciskā norēķina veikšana |
+| FG3-5 | Komandējuma norēķina veikšana |
+| FG3-6 | Kopsavilkuma grāmatošana |