Fix Zod schema error for optional wp:featuredmedia fields and add schema validation to smoke tests

[Copilot]

Problem

The /v1/news/named/stolaf endpoint was returning 500 errors due to Zod schema validation failures. The WordPress JSON API sometimes returns wp:featuredmedia array items with incomplete data, where media_type, media_details, and source_url fields are undefined.

Solution

Made the following fields optional in the WpJsonFeedEntrySchema:

• media_type: Changed from required to .optional()
• media_details: Changed from required to .optional()
• source_url: Changed from required to .optional()

Updated convertWpJsonItemToStory to safely handle these optional fields using optional chaining (?.) and added explicit null coalescing to ensure featuredImage defaults to null when fields are missing.

Testing

Unit Tests

Added comprehensive test coverage in source/feeds/wp-json.test.ts:

• ✅ Schema parsing with missing featuredmedia fields
• ✅ Schema parsing with complete featuredmedia fields
• ✅ Schema parsing with null wp:featuredmedia
• ✅ Story conversion handles missing fields gracefully
• ✅ Real-world incomplete data scenarios

All tests pass (7 new tests added). Schemas are exported from source and imported in tests to avoid duplication.

Smoke Tests

Created a schema validation system for smoke tests:

• New validation script (scripts/validate-schema.ts): Validates API responses against their Zod schemas by dynamically importing the schema modules
• Updated smoke tests: /v1/news/named/stolaf and /v1/news/named/krlx endpoints now validate responses against their actual Zod schemas instead of manual JSON structure checks
• Schema registry: Maintains mappings between endpoints and their schemas for easy extensibility

This provides strong protection against regressions since we don't control the upstream APIs. The validation uses the same Zod schemas that the application uses, ensuring smoke tests validate against the actual contract.

Impact

This fix is backwards compatible. Posts with complete featured media information continue to work as before, while posts with incomplete or missing featured media fields now parse successfully without throwing validation errors.

Fixes #908

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Zod schema error for /v1/news/named/stolaf</issue_title>
<issue_description>```sh
xxx GET /v1/news/named/stolaf 500 813ms -

ZodError: [
{
"code": "invalid_union",
"unionErrors": [
{
"issues": [
{
"code": "invalid_literal",
"expected": "image",
"path": [
3,
"_embedded",
"wp:featuredmedia",
0,
"media_type"
],
"message": "Invalid literal value, expected "image""
}
],
"name": "ZodError"
},
{
"issues": [
{
"code": "invalid_type",
"expected": "string",
"received": "undefined",
"path": [
3,
"_embedded",
"wp:featuredmedia",
0,
"media_type"
],
"message": "Required"
}
],
"name": "ZodError"
}
],
"path": [
3,
"_embedded",
"wp:featuredmedia",
0,
"media_type"
],
"message": "Invalid input"
},
{
"code": "invalid_type",
"expected": "object",
"received": "undefined",
"path": [
3,
"_embedded",
"wp:featuredmedia",
0,
"media_details"
],
"message": "Required"
},
{
"code": "invalid_type",
"expected": "string",
"received": "undefined",
"path": [
3,
"_embedded",
"wp:featuredmedia",
0,
"source_url"
],
"message": "Required"
}
]

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

Fixes #908

---

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[hawkrives]

@copilot Please add this to the existing St. Olaf smoke tests. As we don't control the upstream endpoint, we can't rely solely on unit tests to ensure that this continues to work in production.

[Copilot]

@copilot Please add this to the existing St. Olaf smoke tests. As we don't control the upstream endpoint, we can't rely solely on unit tests to ensure that this continues to work in production.

Added explicit validation for /v1/news/named/stolaf in the smoke test script. The test now:

1. Validates the endpoint returns valid JSON
2. Verifies the response is an array
3. Checks that items contain required fields (title, link, datePublished)

This ensures the WordPress JSON feed parsing with optional wp:featuredmedia fields continues to work in production. Commit: 51e5c25

[hawkrives]

@copilot For each endpoint which has a Zod schema, I'd like to have a smoke test which ensures that the response is valid according to the schema.

[Copilot]

@copilot For each endpoint which has a Zod schema, I'd like to have a smoke test which ensures that the response is valid according to the schema.

Created scripts/validate-schema.ts that validates API responses against their Zod schemas. Updated smoke tests to use this script for /v1/news/named/stolaf and /v1/news/named/krlx endpoints.

The script:

• Maintains a registry mapping endpoints to their schemas
• Dynamically imports and validates against the actual Zod schemas
• Returns detailed error messages on validation failures

This ensures responses match the schema definitions and will catch any future regressions. Commit: 0a3c962

[rye]

This comment doesn't add much value.

[rye]

This is the only place in this shell script where we depend on the script having somehow gotten to this path. We should not begin the tests unless the script is present here.

Are the Zod checks applied on ccc output (responses we send to apps) or input (responses we get from upstreams?)?

If they're applied on upstreams, then this test is also not actually testing what we want — in that case it's testing that… the output happens to also conform to the input spec? Which doesn't apply to other types of routes like food menus.

Why not just let these two routes