feat(intent): postings - declarative source-document-to-ledger posting

[delchev]

What

Fifth accounting-vertical platform PR — postings:, the declarative "documents → ledger" capability the Wave-0 spike was run to shape:

postings:
  - name: salesInvoicePosting
    event: { onTransition: SalesInvoice, model: kf-mod-sales-invoices, when: "Status == 3" }
    creates: JournalEntry              # a LOCAL document entity owning a composition items child
    backReference: SalesInvoice        # the at-most-once guard + the audit link
    map: { entryDate: date, customer: Customer, reason: "Sales invoice {number}" }
    rule: { entity: PostingRule, match: { documentType: "Sales Invoice" } }
    items:
      - { Account: rule(receivableAccount), debit: "Net + Vat" }
      - { Account: rule(revenueAccount),    credit: "Net" }
      - { Account: rule(vatAccount),        credit: "Vat", when: "Vat != 0" }

Semantics (each verified):

• Binds the source's -transitioned topic (feat(intent): -transitioned event channel - workflow transitions become observable #6220) — reactions never see it, so no loops — and re-loads the source by id: the payload is as-of the transition, so the number stamped by a later generateNumber step is correctly picked up by the {number} interpolation.
• At-most-once via the back-reference; event redelivery cannot double-post.
• Fail-soft determination: a missing rule row or a null referenced rule column skips the posting — the document simply stays on the unposted worklist (final-status documents with no back-referencing target, derivable as a lens/report) — never a throw, never a half-post.
• All writes go through the generated repositories → numbering, status init:, and checks: (feat(intent): checks - declarative cross-field and cross-line validations #6223 — the balance invariant) fire on the created document.
• Amounts run through the SDK Calc evaluator with the local item field's scale; row when guards are null-safe; the glue pre-renders every expression Java-side (the expansions convention — the template stays shape-only).

Verification

Unit: GluePostingsTest (full pre-rendering: topic coordinates, guard, ruleRow.* refs, Calc.eval exprs with scale, {placeholder} concat, used-column set) + parser negative tests. Live: the Wave-0 spike's ~100-line hand-written posting listener replaced by the block above — a real invoice flow (approve → issue via the Inbox) produced the identical balanced entry (411 D 1200 / 702 C 1000 / 4532 C 200, customer mapped, VAT row's when passed, re-loaded number in the header) — 6/6 checks. Two shape bugs found and fixed by the live run: the rule entity's Settings perspective package and case-insensitive authored-name matching for map/item/rule references.

Deliberate follow-up (documented): the storno/negation mode + explicit Reverse action — needs the void-document event from the source side first.

🤖 Generated with Claude Code