fix(desktop): restore composer drafts after #2574 remount

[jackwener]

Summary

• fix(ui): drop ceremonial Astryx patches; two-tone shell floor #2574 remounted ChatSurfaceLayout with key={activeId} so scroll state would not leak. That also remounted the Composer and wiped its in-component draft Map. The PR comment claimed drafts lived outside the layout; they do not.
• Remove that remount so session switch / revision flows keep unsent drafts (composer skill leave-return, skill-draft-lifecycle).
• Align two patch-era selectors with stock Astryx (not product fixes):
  • activity-card e2e: role=button instead of data-slot="chat-tool-call-row"
  • skills scroll story: .maka-module-page-rows instead of [aria-label="技能列表"] (List does not forward aria-label)

Test plan

• Desktop: type a draft with skill chips → 新任务 → return to previous session → draft and chips still present
• Revision + disable skill send failure: composer still shows the edited text / skill token
• Storybook smoke: extensions-skills-scroll-containment passes
• activity-card sticky e2e: expandable tool rows still sticky under group expand
• Optional: switch sessions and confirm no severe scroll/new-message bleed (accepted tradeoff vs draft loss)