- bedrock_enabled default: false -> true (was never routing to Bedrock)
- Remove is_bedrock_model check from bedrock_config_if_applicable (model_id
could be 'auto' from server-populated prefs, causing Bedrock to be skipped)
- Default to claude-sonnet-4 when model_id is empty or 'auto'
- fallback_to_warp default: true -> false (no server exists)
- Smoke test: exit immediately on no-text with diagnostic info instead of
polling forever