Remove model/provider from agent persona configs, use context-based resolution
Simplifies agent configuration by removing explicit model and provider
fields from persona JSON configs. Models are now resolved automatically
from context tiers (agent.{app}.{name}) using the providers system.
Key changes:
- Add agent.* context pattern to CONTEXT_DEFAULTS with TIER_FLASH
- Add _resolve_tier() and resolve_model_for_provider() helpers
- Change doctor.json from provider:"claude" to claude:true flag
- Remove provider/model UI from agents app workspace
- Clean up legacy provider/model fields on agent save
- Update CORTEX.md documentation
The claude:true flag is a special case for Claude Code SDK and is NOT
inherited by handoff agents. Provider can still be overridden at request
time for power users via CLI --provider flag.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>