fix(display): a raising display() counts as a circuit-breaker failure (#707)

The first-frame dispatch (_dispatch_first_frame) now asks PluginExecutor.execute_display() to re-raise (raise_errors=True) and records a raise inside the executor as a breaker failure, with the original exception as last_error, instead of a success. The screen is still an empty pass and rotation is unchanged; a hung display() is still recorded once, as a hang. The run-loop golden trace plugin_error.json is regenerated (crashy now records health failures and is skipped by the breaker), and behaviour 7 is dropped from docs/RUN_LOOP_REDESIGN.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/RUN_LOOP_REDESIGN.md

@@ -271,7 +271,3 @@ changed by the restructure.
 6. **A schedule window's end minute is inclusive**, and whether the panel
    turns off at the start of that minute or the end depends on when in the
    minute the first check runs.
-7. **A plugin whose `display()` raises inside the executor counts as "no
-   content"**, and the circuit breaker records it as a success, so it never
-   trips (`plugin_error`, `crashy`). Only an exception raised outside the
-   executor counts as a failure.