intent: a header value may be required when ANY line matches - the legal ground a zero-rated line calls for (#7560)

[nedelcho-delchev-tues]

The rule

ЗДДС чл. 114 ал. 1 т. 12: when an invoice line is zero-rated (or reverse-charged), the document must state the legal ground. As a check: vatGround is required at ISSUED when any line has vatRate == 0. Nothing in the DSL could declare it - requiredWhen guards on the record's own properties (or one to-one hop), itemsCompare reads every line but is warning-only and compares a line to a literal, and a roll-up flag would have needed an ordering operator in when: terms. A 0%-line invoice was issued without a legal requisite.

The change - the issue's shape (a)

checks:
  - { kind: requiredWhen, field: vatGround, whenAnyItem: "vatRate == 0", status: ISSUED,
      message: "A zero-rated line needs its legal ground (VAT Act art. 114)" }

• whenAnyItem: is the when grammar (<Property> ==|!= <literal>, a list = AND) read off each line of the document's items child, inside the repository's gate - the header value is required when any line matches. CheckSupport.itemConditionTerms types the terms; JavaLiterals.conditionExpression renders them; the DAO template loops the lines with the same Criteria query itemsMin uses.
• An amount or a rate compares by value (BigDecimal.compareTo) - vatRate == 0 is the condition the kind exists for, and a boxed equality on a decimal column never holds. A new decimal term type carries that, scoped to line terms.
• The status: gate is required. The lines are read where the document is persisted carrying it, which is also the only moment the question is complete; an ungated rule would read the lines on every REST write (where the controllers read only the row) and refuse a draft assembled line by line.
• when and whenAnyItem compose (ANDed); either alone suffices.
• Refused at parse, each because it would otherwise be inert or wrong: a hop in a line term (a line condition reads the line itself), a property the items entity does not declare, a type an equality is not exact on, a literal that is not a value of that type, an entity owning no items.
• A requiredWhen without whenAnyItem renders byte-identically.

Verified

• engine-intent + ide-template unit suites green, including IntentParserTest.aHeaderValueMayBeRequiredWhenAnyLineMatches (accept + five refusals), EdmIntentGeneratorTest.aRequiredWhenOverTheLinesEmitsTheItemsAndTheirTypedTerms, ModelParameterProcessorTest.aRequiredWhenOverTheLinesRendersItsItemConditionByValue.
• RequiredWhenAnyItemRepositoryTemplateIT (new, 3): the repository template rendered through the platform's own Velocity engine - the items loop at the gate, the by-value comparison, the ANDed record condition, and the unchanged shape without a line condition.
• IntentEmissionCoverageIT green end to end: the fixture's Entry gained vatGround + the rule and EntryLine gained vatRate; over REST, an entry carrying a VatRate: 0 line is refused at POSTED with the authored message, posted once the ground is given, and the plain entry whose lines carry no zero rate still posts with none.
• mvn -T 1C formatter:validate green with the cache wiped.

Not run locally: the rest of the integration suite, the PostgreSQL leg.

Documentation

In-repo: the module guide, .claude/docs/intent-dsl-features.md, and the assistant guide. The three external repos (IntentFile/intent-specification, IntentFile/intentfile.github.io, dirigible-io/dirigible-io.github.io) still need their PRs.

Fixes #7560