refactor(objectql): move the find and findOne bodies into the find facet through the facade port (E2)

.changeset/30020-objectql-find-findone-facet.md

@@ -0,0 +1,13 @@
+---
+'@objectstack/objectql': patch
+'@objectstack/spec': patch
+---
+
+refactor(objectql): the `ObjectQL#find` and `ObjectQL#findOne` bodies move into the find facet
+
+Clause-②: no
+Metadata-protocol: none
+
+- The bodies of `find` and `findOne` move out of `engine.ts` into `engine-find.ts`, the facet that already holds their read helpers. Each method stays on the class as a one-call stub with its signature and its docblock. Where a body handed the engine itself on (`ql: this` in the before/after hook context), it reads the same engine through the host's `facade` entry.
+- No behaviour changes and nothing to do on upgrade. The built declaration files keep every member and every docblock; the source maps move.
+- The `query.fields` and `query.top` liveness rows in `@objectstack/spec` now cite `engine-top-level.ts`, where `planFormulaProjection` and `ENGINE_QUERY_SLOTS` are declared, and `engine-find.ts`, where the `find` / `findOne` bodies fold the `top` alias, since `engine.ts` no longer imports those names; the evidence they cite is unchanged.

docs/qa/platform-checklist/areas/api-backend.json

@@ -2264,7 +2264,7 @@
         "packages/formula/src/stdlib.ts#registerStdLib (registerStdLib — the 29 chained registerFunction calls, isoDate / isoDatetime since #22347, plus label(), the macro bindOptionLabel registers (#26608): 30 bare-callable; the receiver methods `can` and `hasCapability`, from bindPermissionPredicate and bindCapabilityPredicate, are outside the count; calendarDayUtc ADR-0053 D1; addMonthsUtc clamp; the floor/ceil #3306 note), (registerNumericCoercions #1928)",
         "packages/formula/src/validate.ts#CEL_STDLIB_FUNCTIONS (the advertised bare-callable list; its docblock tallies the 30 registerStdLib adds and why a receiver-only name such as `can` is never in it)",
         "packages/lint/src/authoring-rules.ts#EXPRESSION_INVALID (the expression-invalid rule the object save door now dispatches on a formula field, #22031) + packages/metadata-protocol/src/protocol.runtime-authoring-gate.test.ts (the #22019 block: sqrt(record.amount) refused 422 INVALID_METADATA on an active save and on a draft's promotion, nothing lands) + packages/lint/src/runtime-gate.object-formula-writes.test.ts + packages/objectql/src/engine-formula-fault-log.test.ts (the read-path residual: a pre-gate row still reads null, one warn line per object and field)",
-        "packages/objectql/src/engine.ts#applyFormulaPlan (applyFormulaPlan — evaluate-fault → null, the silent-null contract; the evaluateFormulaField docblock states the compile-throws vs evaluate-nulls split)",
+        "packages/objectql/src/engine-top-level.ts#applyFormulaPlan (applyFormulaPlan — evaluate-fault → null, the silent-null contract; the evaluateFormulaField docblock states the compile-throws vs evaluate-nulls split)",
         "content/docs/data-modeling/formulas.mdx (the advertised catalog the matrix cross-checks)",
         "examples/app-showcase/src/data/objects/field-zoo.object.ts + project.object.ts (the stock live-leg formulas)",
         "ADR-0053 Phase 2 D1 (calendar-day timezone contract)",