Add per-project runtime profiles with provider, model, permission, and MCP presets #41
Description
Summary
OAgent already stores project and session metadata, but runtime defaults are still largely global. Advanced users often work across very different environments: one project may want local Ollama with restrictive permissions, while another may need a cloud model, different MCP servers, and a different default permission mode. A per-project runtime profile system would remove repeated setup work and make session startup more deterministic.
Proposed outcome
Each project should be able to define its own preferred runtime profile, including provider, model, permission mode, and MCP configuration defaults. New drafts in that project should start from the project profile rather than from whatever happened to be active globally most recently.
Acceptance Criteria
- Allow a project to persist a runtime profile separate from global defaults.
- Support at least provider, model, permission mode, and MCP server selection in the profile.
- New drafts should initialize from the project profile while existing live sessions keep their own runtime state.
- The UI should make it clear when a session is using project defaults versus explicitly overridden values.
- Include migration behavior for projects created before this feature exists.