Regenerate GenerateContent/ with the GeminiLanguageModel/scripts/typegen
generator from Discovery Document revision 20260929, fixing the drift
reported by the check-data-models CI job.
Generated model changes:
- Structs use optional `var` properties, an empty `init()` and
`Buildable` instead of memberwise initializers.
- Acronyms are capitalized in Swift names (e.g. `responseMIMEType`,
`URLContext`). JSON schema properties are typed as `JSONObject`, and
`Schema`, `DataType` and `VideoMetadata` are no longer generated.
- Enums combine both backends' cases and decode unknown values to
`.unrecognized`.
- Every generated file has a "DO NOT EDIT" header.
GeminiLanguageModel changes:
- Build requests with `Buildable` closures and adopt the renamed
properties. The encoded JSON is unchanged.
- Add `GeminiLanguageModel.Error.invalidResponse(InvalidResponse)`.
Responses that fail to decode or contain a function call with no
name now throw `invalidResponse` instead of `networkFailure`, and
`InvalidResponse.underlyingError` exposes the original error.
- Map the `MODEL_ARMOR` and `JAILBREAK` block reasons and the
`MODEL_ARMOR` finish reason to `guardrailViolation`.
- Exclude the GeminiLanguageModel test READMEs from the root SwiftPM
manifest so builds with `-warnings-as-errors` succeed.
