fix(settings): maintenance tiles start collapsed; remember manual open state

GpuAgentCard was hardcoded :open=true, HeadsCard opened whenever any head
existed, TagEvalCard whenever a persisted run existed — so a fresh Settings
load greeted the operator with several tiles already expanded. All three now
force-open only while their task is actually running (the #877 resurface
behavior on the busy-driven tiles is untouched).

MaintenanceTile additionally persists MANUAL expand/collapse per tile in
localStorage, so the section reloads the way the operator left it; a forced
open while a task runs stays transient and is never saved as a preference.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

frontend/src/components/settings/GpuAgentCard.vue

@@ -3,7 +3,6 @@
     icon="mdi-expansion-card"
     title="GPU agent (CCIP + crops)"
     blurb="Connect a desktop-GPU agent to embed characters (CCIP) and crops. It pulls work over HTTP — your database and Redis stay private."
-    :open="true"
   >
     <p class="fc-muted text-body-2 mb-3">
       The agent is a container you run on the machine with the GPU. It