Add generic production context helpers

README.md

@@ -249,9 +249,57 @@ semantics. `feedback_timestamp` is preserved exactly, including a naive timezone
 It represents the latest ERP feedback, and the ERP export is delayed relative to
 live process data; the adapter makes no freshness inference.
 
-This milestone adds no kg/m² or material-efficiency calculation, ERP-to-ENLYZE
-order mapping, persistence, polling, CLI, or Grafana integration. Automated ERP
-tests use mocks and require no live connectivity.
+Automated ERP tests use mocks and require no live connectivity.
+
+## ERP context normalization
+
+Two pure helpers in `production_analytics.context` prepare context for later KPIs:
+
+- `build_enlyze_production_order(erp_production_order, format_template) -> str`
+  uses an explicit template configured by the caller per machine/workplace.
+  The template requires exactly one literal `{production_order}` placeholder and
+  no other braces; invalid templates raise `ValueError`.
+  Outer ERP-order whitespace is stripped and the
+  remaining order must contain only ASCII digits. Leading zeros are preserved.
+  Empty/invalid orders raise `ValueError`. There is no default machine rule.
+- `extract_nominal_width_m(article_description: str | None) -> float | None`
+  is generic across machines and conservatively reads a single
+  `<width> x <length> m` pair, accepting decimal
+  comma/point and variable whitespace. For example, `Stex R 1501 C (PR) 5,80 x 50 m`
+  yields `5.8`. Earlier article numbers and trailing descriptive text are ignored.
+  Missing, malformed, multiple or chained dimension patterns return `None`, as do
+  non-positive/non-finite dimensions. Signed/scientific notation and other units
+  are deliberately unsupported; both dimensions must be positive plain numbers.
+
+K7 currently uses the explicit template `K 7-{production_order}`:
+
+```python
+k7_order_template = "K 7-{production_order}"
+enlyze_order = build_enlyze_production_order("12026000815", k7_order_template)
+# "K 7-12026000815"
+```
+
+Future machines may supply different verified templates without changing the
+generic helper. Template selection belongs to machine/workplace configuration
+or adapters; the helper contains no workplace lookup or machine-specific branch.
+No other machine rule is introduced here.
+
+ENLYZE production-order identifiers remain opaque everywhere else, with exact
+comparison. These helpers never reverse-parse or split ENLYZE orders, including
+combined identifiers such as `K 7-12025000074-K 7-12025000075`; passing such an
+identifier to the ERP mapping function is rejected.
+
+Nominal finished-product width currently comes from ERP article-description
+parsing because neither verified DWH view (`dbo.GRAFANA_WORKPLACE_STATUS` and
+`dbo.GRAFANA_PRODUCTION_CONFIRMATION`) has a dedicated width column. ENLYZE
+`wLg1MeasuringWidth` (`Produktbreite`) is explicitly not used as K7 nominal
+finished-product width:
+it belongs to the MAHLO measurement system and observed values differ from nominal
+article widths. Structured ERP product master data would be preferred when available.
+
+These helpers are independent of database access and are not yet wired into live
+processing. No normalized context model, kg/m² or material-efficiency calculation,
+persistence, polling, runner, timeseries, or Grafana changes are introduced here.
 
 ## Peak-cycle detection