Subagents and Compact on the server's /api/v2 facts (server 2.0.0-beta.7)

- Models' `subagents {offered, named_only}` and /models' `subagents_cap`; a chat's
  `subagents {offered, named_only, cap}` decides the chip for an open chat (an agent chat
  gets none where the server says so); `named_only` shows the spec's `own` line in the
  popover and marks the chip. GET /chats/{chat}/team stays the fallback for older servers.
- Context: `auto_compact`, `until_compact` and `compactable` from the server (worked out from
  `threshold` with an older one); Compact greyed while not compactable.
- "Tasks: N" for a task's nested fold, the server's sentence; the subagent words aligned with
  the server's catalogues (Podagenti, Sottoagenti, Podagenci); hint says the same-model rule.

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

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