web-ui: session top bar follow-ups — fork badge, and apps/skills/keychain join the quick tools (#485)

Follow-ups to the session top bar. The status pill ("working" / "needs you") is removed — the transcript already shows both states. In its place, a session created by forking shows a small fork badge; clicking it opens the conversation it was forked from. The quick-tool row grows from crons/files/memory to crons, files, apps, skills, memory, and keychain, and the apps, skills, and keychain views opened from a session's bar get the scoped treatment the others already had: filtered to the session's context (skills keep org-wide entries visible), the scope picker locked, and the scoped top bar persisting with the title linking back to the chat.

**Deployment notes**

Web-UI only. One visible change: the status pill ("working" / "needs you") no longer appears in the session top bar.

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