Session 2 wrote both 'binding' (singular) and 'bindings' (plural)
in form_submissions.schema_snapshot for backward compatibility. With
no production data yet and dev seeders re-running every cycle, dual-
key state has no upside. Snapshots now write 'bindings' only;
all readers updated to match.
FormFieldBindingService::snapshotShapesFor() simplified to return
only ['bindings' => $all]. Pre-existing
SchemaSnapshotEmbedsBindingFromRelationalTableTest updated to assert
the applicator shape (with id, merge_strategy, trust_level,
is_identity_key) on bindings[0]; new
SnapshotOnlyContainsBindingsKeyTest enforces the no-legacy-key
contract going forward.
FormBuilderDevSeeder template snapshot embeds 'bindings' => [] for
form-owned fields (Pattern B) instead of 'binding' => null.
Other 'binding' string occurrences in the codebase (FormFieldResource,
FormFieldService, request validation rules, BindingConflictResolver
internal helper key) are unrelated to snapshot dual-state and remain
untouched.
Refs: WS-6 session 2 deviation #9 cleanup
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>