feat(openai-codex): add gpt-5.3-codex-spark and robust responses stream handling

[aShanki]

Summary

• add gpt-5.3-codex-spark to OpenAI Codex model list with Spark-specific metadata (contextWindow: 128000, maxTokens: 8192, supportsImages: false)
• harden OpenAI Codex Responses event parsing to handle done-only/content-part streams so assistant text/tool calls are emitted reliably
• add tests for Spark model metadata and done-only/content-part stream fallback behavior

Testing

• pnpm vitest run api/providers/tests/openai-codex.spec.ts api/providers/tests/openai-codex-native-tool-calls.spec.ts (in src)
• pnpm --filter @roo-code/types test -- src/tests/provider-settings.test.ts
• pre-push hook: full monorepo check-types

Notes

• this fixes the runtime issue where Codex Spark could return no assistant messages even with a valid API response

Start a new Roo Code Cloud session on this branch