Compact sidebar thread cards: hide the branch/provider line

[vincent-caetano]

Problem

Every sidebar thread card spends its third line on the worktree/branch name, the environment icon and the provider badge. When I scan the sidebar I pick threads by project and title. The branch, provider and environment are things I only check after opening a thread, and they're already in the hover card. That line makes every card about a third taller and adds noise. The one useful thing on it is the PR badge.

Proposal

An opt-in Compact thread cards setting (Settings → General, off by default):

CURRENT                                         COMPACT
┌───────────────────────────────────────┐       ┌───────────────────────────────────────┐
│ [A] acme-web                   ✓ Done │       │ [A] acme-web ▤ ✳              ✓ Done │
│ Add CSV export                        │  →    │ Add CSV export                ⑂ +3    │
│ 📁 feat/csv-export         ⑂+3 ▤ ✳CF  │       └───────────────────────────────────────┘
└───────────────────────────────────────┘

• Branch line removed.
• Environment and provider icons move, smaller (12px) and without the instance badge, to just after the project name.
• PR badge (and running-terminal status) moves next to the title.
• The hover card is unchanged and still shows branch, environment and provider/model.

Default behavior doesn't change, and nothing becomes unreachable.

Implementation

I opened a PR with this so you can try it: #33669

Before	After (two cards simulated as remote to show the environment icon)

Happy to change the shape: for example, a per-item "show on cards" list like the thread details items, or making it part of the existing card instead of a setting.