feat(core,io): persist nest status and made-by in nest files

Add NestStatus (Quote/ToBeCut/HasBeenCut) plus MadeBy on Nest, written as
additive camelCase nest.json fields with PascalCase enum strings matching
the units convention. Legacy files and unknown status values fall back to
Quote. The nest info dialog gains a Status dropdown and Made By box.

docs/nest-file-format.md

@@ -4,6 +4,14 @@
 Old files remain readable. Older applications ignore the new cutting-state fields;
 opening and saving with an older application loses that state.
 
+## Job metadata
+
+`nest.json` carries the workflow fields shown in the nest info dialog:
+`name`, `customer`, `dateCreated`, `dateLastModified`, `notes`, `material`,
+`thickness`, plus `status` (`"Quote"`, `"ToBeCut"`, `"HasBeenCut"`) and `madeBy`.
+Status and made-by are additive: files written before them load as Quote with an
+empty maker, and an unrecognized status value likewise falls back to Quote.
+
 ## Programs and placements
 
 - `programs/program-N` is drawing N's clean G-code program; optional