[Bug] Postgres client using `.toCamel()` causing JSON keys containing upper snake case to lose their underscores

[thomasjiangcy]

What happened

When using OpenWorkflow with the Postgres backend, JSON keys inside workflow run input are being mutated during persistence/readback.

Observed persisted payload snippet:

{
  "env": {
    "OPENAIMODEL": "gpt-5.3-codex",
    "OPENAIBASEURL": "http://127.0.0.1:8090/...",
    "OPENAIREASONINGEFFORT": "medium"
  }
}

Expected:

{
  "env": {
    "OPENAI_MODEL": "gpt-5.3-codex",
    "OPENAI_BASE_URL": "http://127.0.0.1:8090/...",
    "OPENAI_REASONING_EFFORT": "medium"
  }
}

Why this is a bug

Workflow input payloads should be stored and returned without rewriting user-provided JSON keys.

Reproduction

1. Start OpenWorkflow with the Postgres backend.
2. Enqueue a workflow run whose input includes JSON object keys with underscores (e.g. OPENAI_MODEL, OPENAI_BASE_URL).
3. Let the run persist.
4. Query the workflow run input from the workflow_runs table.
5. Observe underscores are removed from JSON keys (e.g. OPENAI_MODEL becomes OPENAIMODEL).

Expected behavior

JSON input keys are preserved exactly as provided.

Actual behavior

JSON input keys are transformed during persistence/readback.

Suspected root cause

The Postgres backend applies postgres.toCamel transform globally. In postgres (postgres.js), this transform also applies to JSON value object keys, not only SQL column names.