Editing an agent no longer keeps its max-turns limit

What changed

The v2 agent edit dialog no longer surfaces or preserves the agent's max_turns configuration. Saving any configuration change (avatar, permission mode, env vars, soul mode, heartbeat, …) sends an explicit removal for max_turns alongside only the edited keys, so a previously-set per-agent turn cap is dropped without replacing unrelated configuration.

Why this matters to the user

An agent that had a max_turns limit set (e.g. carried over from v1 or set through an earlier build) silently loses it the next time the user edits that agent in the library. There is no field in the v2 edit UI to view or restore it, so the agent reverts to the runtime default turn behavior.

What the user should do

Nothing — automatic. max_turns is being retired from the per-agent configuration in v2; agents run under the default turn behavior.

Notes for release manager

• The main-process runtime still reads agent.configuration.max_turns (src/main/ai/runtime/claudeCode/settingsBuilder.ts:304). The retirement is currently only enforced at the edit-form layer, so the field is dropped on edit but still honored at runtime if present. Follow-up: remove the runtime read to fully complete the retirement, or re-surface the field if the cap is meant to stay. Tracked as inherited from feat/chat-page.
• Behavior is inherited verbatim from feat/chat-page (added in 5383513090 feat(agent): enhance agent configuration with permission mode and soul mode options); the durable change belongs upstream there as well.