Accepts ADR-0002: the datamodel document's JSON Schema

[johnnyt]

Flips ADR-0002 (the datamodel document's JSON Schema) to accepted. Its code shipped in statifier_datamodel 0.5.0 (tag v0.5.0 at 71de7e0); acceptance was given by the operator on 2026-09-27.

What changes

• docs/adr/0002-datamodel-document-json-schema.md: the status line moves from proposed (2026-09-26) to accepted (2026-09-27) in place, the date moving with the word as ADR-0001's own flip did; a dated ## Note at the foot records the flip, the version and the SHAs verified at.
• docs/adr/README.md: the ADR-0002 row's status cell moves to accepted.

git diff origin/main -- docs/adr/ removes two lines: the record's status line and the index row whose status cell moved. Every other line is an addition at the foot of the record. No code, no changelog fragment (changelog.d/README.md excludes ADRs).

Direction check (every claim against the tag and main)

Verified at 71de7e0 (the v0.5.0 tag) and at fde6da6 (origin/main). The one commit between them touches .claude/wurk/release.md only, and no commit after the record merged (c631e97) touches the record's cited files other than the code commit c61a52a and the release commit 71de7e0 (version bump, README pin, changelog).

• Context, index/1 admits any map with a list under "scopes" and answers nil otherwise: StatifierDatamodel.Index.index/1. Holds.
• Context, an unknown scope name indexes with scope: nil: Index's private scope_name/1 answers nil for a name outside @scopes. Holds.
• Context, a runtime dependency is a decision to record: mix.exs, the comment above deps/0. Holds.
• Decision 1, the file, its draft and the package list: priv/schemas/datamodel-document.schema.json carries the draft-07 $schema; priv/schemas is in mix.exs package/0 files:. Holds.
• Decision 2, the drift test over the nine and one outside: test/statifier_datamodel/schema_test.exs, "each spelling the schema lists indexes to a type; one outside them does not", against index.ex's private @types. Holds.
• Decision 3, StatifierDatamodel.Schema.path/0 and json/0, embedded with @external_resource, text not a map, no caller in lib/: lib/statifier_datamodel/schema.ex; a search of lib/ finds no other reference to the module. Holds.
• Decision 4, advisory: the near-misses are rejected by the schema and index as before: schema_test.exs, "the near-misses". Holds.
• Decision 5, the required keys and their types: the file's definitions (scope, entry, declaration, field) and top-level required. Holds; the keys the decision names without a type are required and untyped in the file, which the foot Note records as a reading, not a change.
• Decision 6, type and item_type are strings and the nine are listed under definitions/closed_type: the file; the declared-name case is schema_test.exs, "an entry whose type names a declaration validates". Holds.
• Decision 7, no additionalProperties: false anywhere: the file has no additionalProperties key. Holds.
• Decision 8, the $id keyed on document version 1: the file's $id; schema_test.exs, "the file is draft-07 and its $id is keyed on document version 1". Holds; the URL does not resolve, which the decision already allows ("never fetched") and the foot Note records.
• Decision 9, a change to what the document admits is breaking: changelog.d/README.md. Holds.
• Decision 10, ex_json_schema ~> 0.11, only: :test: mix.exs deps/0; mix.lock resolves 0.11.5. Holds.
• Worked example rows (nine declared paths; eight without event; card.last4 not sensitive; Settleable undeclared and read as opaque; version 2 indexed as 2; the declared-name entry typed {:declared, "cards.credit_txn"}): schema_test.exs negatives/0 and StatifierDatamodel.Types.parse/2's opaque answer. Holds.

No claim failed. The record's own sentence "this record does not flip its own status" stays true and is met in the foot Note: the operator flipped it.

Gate

mix quality ran green on the committed tree (format, compile with warnings as errors, doc links, dependencies, credo, docs, tests with coverage, dialyzer).