Literal types for column defaults: codecs name the literals they accept (ADR 254)

docs/architecture docs/ADR-INDEX.md

@@ -36,6 +36,7 @@ This document provides a comprehensive index of all Architectural Decision Recor
 | 249 | Central attribute-spec registry | Registers every model-level and field-level PSL attribute of both families in one place, keyed by level and name, as a spec *factory* over a framework-owned construction-time context (`AttributeSpecContext` / `FieldAttributeSpecContext`) — the uniform signature is what lets the language server invoke the same factories the interpreters run. `assembleAttributeSpecs` merges family built-ins with [ADR 236](adrs/ADR%20236%20-%20Target-contributed%20model%20attributes.md)'s model-attribute descriptors into frozen plain records and restores the factory types core erases (they return `AttributeSpec<never>`, because `refine` makes `Out` contravariant and `unknown` would reject every spec that refines). Registry keys drive unknown-attribute diagnostics at field and model level in both families; block attributes are declared on `AuthoringPslBlockDescriptor.attributes` and parsed by the kit. | [ADR 249 - Central attribute-spec registry.md](adrs/ADR%20249%20-%20Central%20attribute-spec%20registry.md) |
 | 250 | Models and views are emitted from the contract | `contract.d.ts` gains a `Models` namespace (one member per model, `<ns>_<Model>`, plus `<ns>_Any<Base>` for each polymorphic base) and a type-only `models` constant; relations are typed as the related member with a phantom `RelationKeys` key so `Scalars<M>` names a default fetch's row and `Shape<M, Spec>` names an application data structure derived from the model, and both ORM collections carry `_row` so `ResultType` names any query's result. To-one nullability is a family hook (SQL reads foreign keys and column nullability; Mongo takes the nullable default); name collisions and non-identifier names are emitter errors | [ADR 250 - Models and views are emitted from the contract.md](adrs/ADR%20250%20-%20Models%20and%20views%20are%20emitted%20from%20the%20contract.md) |
 | 253 | PSL red-root source ownership | A PSL parse registers the actual returned red document root with a named `SourceFile`; post-parse diagnostics resolve filenames from the node's owning root through `PslSources`, with no unnamed parse mode or singleton fallback. Output diagnostics may still serialize a `sourceId`, but it originates from `SourceFile.filename`; file-read errors and Prisma7 compatibility plumbing are explicit exceptions. | [ADR 253 - PSL red-root source ownership.md](adrs/ADR%20253%20-%20PSL%20red-root%20source%20ownership.md) |
+| 254 | Literal types for column defaults | Every literal column default has a literal type (`string`, `boolean`, the whole-number types by size `i8`–`i64`, `bigint`, `decimal`, `float`, `json`, or a list of those), so a codec descriptor names the types it accepts and gains no methods; a written number's type comes from its own size and precision, never from the column. A codec converts between a named type's value shape and its own stored form inside `decodeJson`. PSL writes a literal as a plain scalar or as an ADR 129 tagged literal (`` json`...` ``); `sql` writes a raw SQL expression instead. Codecs never see PSL syntax. Replaces the PSL half of ADR 184 | [ADR 254 - Literal types for column defaults.md](adrs/ADR%20254%20-%20Literal%20types%20for%20column%20defaults.md) |
 
 ## Query System
 

docs/architecture docs/adrs/ADR 184 - Codec-owned value serialization.md

@@ -2,6 +2,8 @@
 
 > **Retrospective note.** This ADR's examples use the `defineCodec({...})` factory. That factory was the canonical codec-author surface at the time; it was later retired in favor of class-based authoring: concrete codecs extend `CodecImpl`, descriptors extend `CodecDescriptorImpl`, and per-codec column helpers tie helpers to descriptors with `satisfies`. The ADR's *decision* — that codecs own both wire and JSON-safe representations through `encode` / `decode` + `encodeJson` / `decodeJson` — is unchanged; only the authoring shape has moved on. See [ADR 208 — Higher-order codecs for parameterized types](ADR%20208%20-%20Higher-order%20codecs%20for%20parameterized%20types.md) and the [Codec authoring guide](../../reference/codec-authoring-guide.md) for the current shape.
 
+> **PSL half: see [ADR 254 — Literal types for column defaults](ADR%20254%20-%20Literal%20types%20for%20column%20defaults.md).** The `PslLiteralCodec` interface sketched below is replaced there: codec descriptors name the literal types they are compatible with, codecs gain no methods, and codecs never receive PSL syntax. The JSON half of this ADR is unaffected.
+
 ## At a glance
 
 A column with `codecId: "pg/timestamptz@1"` has a default value of `new Date('2024-01-15')` — a JavaScript `Date`. This value has to survive a round-trip through `contract.json`, but `Date` has no JSON representation. The codec handles it: