Updated the animation draw pipeline to avoid repeated layout recomputation, which was causing layout jitter during animations. Auto‑layout now only runs when the layout is actually dirty or on the initial draw, and layout dirtiness is tracked across format calls, subplot/panel creation, and user‑driven size changes. Added a regression test to ensure draw_idle no longer retriggers layout. CI has been hardened: selected‑test mode now falls back to the full suite when nodeids are missing (exit code 4/5), baseline generation does the same on base commits, and coverage is collected in a single‑process pass to avoid xdist worker gaps. Finally, CI logs were made quieter with short tracebacks and warnings suppressed so failures are easier to spot.

Closes #488