feat(print): feeder resolves line-item to-one relations — {{Unit}} renders in items columns (#6501)

[delchev]

Closes #6501.

What

The generated <Entity>PrintFeeder fed each line-item row only its scalar fields, so a print template's items table could not render the line's unit or product — while header relations resolved to full maps + __label. Line-item to-one relations now resolve the same way:

• PrintFeederSupport contributes itemNodes — one per to-one relation of the line-items entity, the composition back-reference to the document excluded (that is the header itself). Same shapes as the header nodes: a same-model target names its fields one by one (the generated Java stays the audit of what a print receives); a cross-model target is copied reflectively per the Intent: removing a field silently invalidates cross-model consumers' generated code #6422 rule, so this project's committed gen/ survives the owner retiring a field. Item variables are item-prefixed so a header relation of the same name (Customer on both) cannot collide.
• The template loads the target per row through its generated repository (validations + the multilingual translation overlay apply — a bg request prints "1 месец"), caches lookups per distinct key rather than per row, and hangs the map (with __label) under the relation's own key — so {{Unit}} renders the label and {{Unit.Name}} descends, exactly like the header relations.
• generateUtils.js passes the new collection through with the same gen-folder/package derivation as the header nodes.

Tests

• PrintFeederSupportTest.itemToOneRelationsAreFedWithLabelAndFields — back-ref exclusion, Settings-perspective routing, prefixed variables, same-model named fields vs cross-model none (5/5 green).
• IntentEmissionCoverageIT — BillLine gains a Unit relation (the multilingual setting — the literal "1 month" case); the generated BillPrintFeeder is asserted to contain the distinct-key cache, the repository load, the __label put and the row-key hang — and the fixture app compiles and publishes end-to-end (1/1 green locally), so the emitted Java went through real javac.

🤖 Generated with Claude Code