TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 3.
Adds _render_warmup_status_indicator_result(app) -> Result[dict] helper that
wraps the controller.warmup_status() try/except in
render_warmup_status_indicator. The data field carries the status dict so
the legacy wrapper can use it for rendering without an additional instance
attribute.
render_warmup_status_indicator becomes a thin wrapper that drains errors
to app.controller._worker_errors under the controller's lock (worker error
plane; thread-safe per app_controller pattern).
Audit: BROAD_CATCH count 18 -> 17, COMPLIANT count 19 -> 20. Migration
target count drops from 42 to 34 (8 sites migrated). Tests: 2/2 pass.
ed
0dacbfce62