Parse terminal JSON action blobs into structured tool calls #296

Several terminal-style datasets preserve assistant JSON action blobs as plain message text. These often include fields such as analysis, plan, commands, and task_complete. A stricter standardized form would put analysis/plan in message or reasoning fields, convert commands to terminal tool calls, and convert completion signals to finish.

Known affected families include LiteCoder terminal, Nemotron terminal, OpenThoughts-Agent, and possibly other terminal traces with the same JSON response format.

Acceptance criteria:

• Add a reusable parser for the terminal JSON response format.
• Convert command batches to structured terminal tool calls when the JSON parses safely.
• Preserve original raw text/provenance in extra when parsing succeeds.
• Regenerate affected samples and validate them.