feat(engine-intent): cross-model generates SOURCE (fromUses:)

[delchev]

What

Adds fromUses: to a generates (create-from) block: an optional model alias for the source
entity. Until now the source had to be local (from:) and only the target could be foreign (uses:);
this is the mirror — a foreign source with a local target. Fully backward compatible: a generates
without fromUses: renders byte-identically (the new template variables default to the local values).

# authored in `delivery-notes`, whose DeliveryNote already references inventory's GoodsIssue
generates:
  - name: delivery-note-from-goods-issue
    from: GoodsIssue
    fromUses: inventory        # the SOURCE is owned by the `inventory` model
    to: DeliveryNote           # the TARGET is local
    forEntity: GoodsIssue

Why

Not symmetry for its own sake — it removes a class of unbreakable module dependency cycle.

"A generates into B" authored in A puts a reference to B's entities inside A's generated controller.
When B already holds a foreign key back into A — which is usually why the create-from exists — the
two modules' generated Java is mutually dependent. Under the runtime model that is invisible, because
every project compiles in one flat batch. The moment modules are compiled and published
independently (AOT packaging, #6400 / #6592), it is fatal: neither member of the pair can be built
first, so neither can ever be released.

Authoring the same create-from on the module that owns the target, with fromUses: A, leaves exactly
one edge — B → A — and the pair is a DAG again. This is the same reasoning that made a schedule's
source addressable across models in #6532.

Found while unblocking AOT jar packaging for a 79-module suite: two pairs were mutually dependent, and
with this keyword the whole graph became acyclic and all 31 Java-bearing modules now compile
leaf-first against the released 14.18.0 SDK.

How

• GeneratesIntent: fromUses + isCrossModelSource().
• IntentParser: the alias must be declared under uses:; the source, its items and its status
  relation are no longer validated against this model (they resolve from the owner's .model, exactly
  as a cross-model target already does). forEntity must be the source — the button is contributed
  onto the owner's view, and no local view carries the source id the endpoint needs. The
  unknown-local-source message now points at the new key.
• CrossModelSupport.TargetInfo: new statusProperty, read off the owner .model's
  DOCUMENT_STATUS widget — the same fact RelationIntent.isEntityStatus() carries locally — so the
  sourceStatus: completion hook works for a cross-model source. It is never guessed: the status
  FK is author-named (Status / Stage / State), and a wrong guess would emit updateProperty
  against a non-existent column, failing only on the button's first click.
• GlueIntentGenerator + generateUtils.js + Generate.java.template: fromGenFolder /
  fromProjectName point the source half at the owner's gen folder and at the -transitioned topic of
  the project that owns the source, so the owner's postings and integrations observe the flip
  unchanged. Both default to the local values.
• GeneratesIntentGenerator: the button registers on the owner's <owner>-custom-action point —
  the point that view actually reads — while the descriptor file and the controller stay in the
  authoring project.

Verification

• Guide section documenting the keyword, when to reach for it, and its rules.
• New parser coverage (accepts a cross-model source with no local source entity; rejects an undeclared
  alias; rejects a forEntity that is not the source) and glue coverage (owner gen folder + owning
  project resolved; a local generate keeps the markers empty).
• engine-intent suite: 347 tests, 0 failures.
• Exercised end to end on two real module pairs: the emitted controller reads
  gen.inventory.data.goodsissue.* / gen.opportunities.data.opportunity.*, writes the local target,
  registers on inventory-custom-action / opportunities-custom-action, and emits
  updateProperty(id, "Stage", 3) + opportunities-Opportunity-Opportunity-transitioned — the
  author-named property and the owner's project, both read from the owner model.

🤖 Generated with Claude Code