Migrate JSON ingestion specs into gem

[jwils]

Why

The JSON ingestion gem should own the JSON-schema tests that cover its extracted implementation so the gem can enforce full coverage without a SimpleCov skip.

What

• Move JSON schema generation, metadata merge, pruner, and matcher specs into elasticgraph-json_ingestion.
• Add JSON-ingestion artifact-manager integration coverage for versioned schema artifacts, version-bump enforcement, metadata refresh, and schema evolution diagnostics.
• Add focused wrapper/scalar specs for the remaining extracted JSON-ingestion paths.
• Remove the temporary SimpleCov filter for elasticgraph-json_ingestion.

Verification

• script/run_gem_specs elasticgraph-json_ingestion
• script/type_check elasticgraph-json_ingestion
• BUNDLE_GEMFILE=Gemfile bundle exec rspec --format progress spec/integration/elastic_graph/schema_definition/rake_tasks_spec.rb spec/unit/elastic_graph/schema_definition/runtime_metadata/scalar_types_by_name_spec.rb from elasticgraph-schema_definition/
• bundle exec standardrb ... on touched specs/support

script/run_gem_specs elasticgraph-schema_definition and script/run_gem_specs elasticgraph-json_ingestion both pass with 100% coverage (with the test datastore booted).

Follow-ups

• The migrated spec files keep the compact module JSONIngestion::SchemaDefinition form so that git/GitHub detects them as file moves. A follow-up PR (after this stack merges) will convert them to the standard nested module style and re-indent.
• The JSON-schema-versioning scenarios that the new schema_artifact_manager_extension_spec.rb covers have been removed from the core rake_tasks_spec.rb; the core lines they exercised are now covered by focused unit specs instead.

Stack

Current PR is marked with ->.

• #1199 Add JSON ingestion gem shell
• #1200 Add schema definition extension plumbing
• #1201 Move JSON schema helpers to json ingestion gem
• #1203 Namespace JSON schema helpers under JSON ingestion
• #1204 Add JSON ingestion indexing extensions
• #1215 Wire JSON ingestion schema extension modules
• #1205 Use JSON ingestion as schema definition extension
• #1202 Document JSON ingestion schema APIs
• -> #1224 Migrate JSON ingestion specs into gem
• #1220 Add configurable indexing event decoder

[jwils]

Addressed in 3dd2511 on this PR.

[myronmarston]

Not done reviewing but want to submit my feedback so far...

[myronmarston]

Beyond the feedback below:

• Can we add elasticgraph-json_ingestion to the list of gems that run in parallel in

  elasticgraph/script/run_gem_specs

  Line 32 in ac2c10e

  if [[ "$gem" == "elasticgraph-graphql" || "$gem" == "elasticgraph-indexer" || "$gem" == "elasticgraph-schema_definition" ]]; then

  ? I measured rspec vs flatware_rspec and found that flatware makes the json-ingestion test suite quite a bit faster.
• I audited the remaining mentions of json in elasticgraph-schema_definition and here's what I found...

elasticgraph/elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/built_in_types.rb

Lines 893 to 898 in f32b634

	# Allow any JSON for this type. The list of supported types is taken from:
	#
	# https://github.com/json-schema-org/json-schema-spec/blob/draft-07/schema.json#L23-L29
	#
	# ...except we are omitting `null` here; it'll be added by the nullability decorator if the field is defined as nullable.
	# In the index we store this as a JSON string in a `keyword` field.

should be moved to

elasticgraph/elasticgraph-json_ingestion/lib/elastic_graph/json_ingestion/schema_definition/factory_extension.rb

Line 46 in f32b634

"Untyped" => {type: ["array", "boolean", "integer", "number", "object", "string"].freeze},

Some RBS signatures remain to migrate (or just remove if already copied over):

sig/elastic_graph/schema_definition/schema_elements/field.rbs:12:        type jsonSchema = untyped
sig/elastic_graph/schema_definition/schema_elements/type_with_subfields.rbs:58:          # ?json_schema: SchemaElements::Field::jsonSchema,
sig/elastic_graph/schema_definition/test_support.rbs:8:        ?json_schema_version: ::Integer,
sig/elastic_graph/schema_definition/test_support.rbs:20:        ?json_schema_version: ::Integer,
sig/elastic_graph/schema_definition/api.rbs:5:    type jsonSchemaLayer = :nullable | :array
sig/elastic_graph/schema_definition/api.rbs:6:    type jsonSchemaLayersArray = ::Array[jsonSchemaLayer]

(Note: these latter 2 are not really related to the PR as they aren't tests, but now that the tests have move this is the first point an audit was possible. Feel free to move those in a follow up PR).

Beyond that, this LGTM!