workspace skeleton: UAPF 2.2.0 layout + L0 enterprise index

Step 1 of the vk-gramatvediba build.

- normative folder structure: enterprise/ , domains/ , processes/
- enterprise/enterprise.yaml — L0 enterprise index (validates against
  the UAPF 2.2.0 enterprise-index schema; packages[] filled in later steps)
- README and docs/conventions.md — VK function-group to UAPF level
  mapping, composition rule, transcription-fidelity policy
- CODEOWNERS placeholder and .gitignore (built .uapf archives excluded)

Targets UAPF specification v2.2.0.

docs/conventions.md

@@ -0,0 +1,60 @@
+# Conventions — VK accounting processes mapped to UAPF levels
+
+## Level mapping
+
+| UAPF level | VK concept | Location |
+|-----------|-----------|----------|
+| L0 — enterprise index | The VK / VPC accounting workspace as a whole | `enterprise/enterprise.yaml` |
+| L1 — domain | The accounting domain (*grāmatvedības uzskaite*) | `domains/gramatvediba/` |
+| L2 — function group | Each function group, FG1–FG6 | `processes/fgN/` |
+| L3 — sub-process variant | A sub-process that decomposes into variants | `processes/fgN-x/` (only where needed) |
+| L4 — atomic executable | A single runnable process (BPMN + DMN + resources) | `processes/fgN-x/` |
+
+The six function groups:
+
+| FG | Domain |
+|----|--------|
+| FG1 | Long-term non-financial assets and inventory accounting |
+| FG2 | Financial assets accounting |
+| FG3 | Liabilities and expenses accounting |
+| FG4 | Remuneration liabilities accounting |
+| FG5 | Receivables and revenue accounting |
+| FG6 | Report preparation for publication |
+
+L3 is used only where a sub-process genuinely decomposes into variants. An
+atomic sub-process — for example FG3-1, *Rēķina saņemšana par
+precēm/pakalpojumiem* (invoice receipt) — is an L4 package included directly
+by its function-group (L2) package.
+
+## Composition
+
+Higher-level packages reference lower-level ones through the manifest
+`includes` field; they never copy BPMN, DMN or CMMN artifacts (UAPF
+specification 2.2.0, §05 — no-duplication rule). The VK schemas link heavily
+between function groups; those cross-function-group links are likewise
+expressed as `includes` references.
+
+## Source of truth and engine consumption
+
+The Git repository is the single source of truth. Each package is a
+human-readable, diff-able directory: `uapf.yaml` plus cornerstone folders
+(`bpmn/`, `dmn/`, `cmmn/`, `resources/`) and `metadata/`.
+
+The UAPF reference engine (`uapf-engine`) consumes packages as `.uapf`
+archives. A package directory is exported to a `.uapf` archive — a zip that
+preserves file paths and the manifest — for execution and validation. The
+archives are build artifacts; they are not committed to the repository.
+
+## Transcription fidelity
+
+Packages are transcribed from the published VK process schemas (flowcharts)
+and process registers (step tables). The transcription preserves:
+
+- step identifiers (the VK `process nr.` numbering);
+- responsibility — RACI columns map to BPMN lanes (Iestāde / Nodarbinātais / VPC);
+- the information system each step uses — mapped to a capability binding;
+- execution deadlines (SLAs) and the data objects each step produces.
+
+The transcription does not change the documented process. Where a schema and
+its register disagree on sequence, the discrepancy is recorded in the package
+documentation rather than silently resolved.