docs: add Gradium custom voice and custom transcriber guides - #1158

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

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Discriminated union "UpdateToolsResponse (update > tools > Response)" lists "#/components/schemas/GhlTool" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.

Discriminated union "UpdateToolsRequestBody (update > tools > Request > Body)" lists "#/components/schemas/UpdateCodeToolDTO" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.

Discriminated union "UpdateToolsRequest (update > tools > Request)" lists "#/components/schemas/UpdateCodeToolDTO" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.

Discriminated union "DeleteToolsResponse (delete > tools > Response)" lists "#/components/schemas/GhlTool" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.

Discriminated union "GetToolsResponse (get > tools > Response)" lists "#/components/schemas/GhlTool" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.

Discriminated union "CreateToolsResponse (create > tools > Response)" lists "#/components/schemas/GhlTool" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.

Discriminated union "CreateToolsRequest (create > tools > Request)" lists "#/components/schemas/CreateCodeToolDTO" in its oneOf/anyOf, but it is not present in the discriminator mapping. This variant will be omitted from the generated union, so payloads using it will fail to serialize or deserialize. Add it to the discriminator mapping to include it.