A variant group appears in the feed as one `choose` item that opens its deck #1411

Part of #587 (P1 Feed), the last piece of #1051; waits for #1410 (the deck).

Done looks like.

• [ ] The feed shows a variant group as one item of type choose (not n separate pull items), naming the tell and the number of siblings still open, linking to the deck.
• [ ] Once one sibling is shipped or all are closed, the item reads as decided and no longer asks.
• [ ] Tests: two sibling pulls give one choose item; a decided group gives none that asks.
• [ ] A new test file is added to GATE in scripts/gate.ts in the same push (bun test test/check-list.test.ts is green); the last two tries went red on exactly this.

Files. src/feed/items.ts, src/feed/feed.ts, a test.

Parked by the crew: the check failed ("surfaces adversarial: web > N+1: needsYouCard does not cost more as agent pulls span more distinct repos") and the decider saw no point in another try (pull #1747 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Parked by the crew: the check failed and the decider saw no point in another try (pull #1752 closed).

Parked twice since a person last spoke here, so it is the planner's now. Every reason:

1. the check failed ("surfaces adversarial: web > N+1: needsYouCard does not cost more as agent pulls span more distinct repos") and the decider saw no point in another try (pull #1747 closed)
2. the check failed and the decider saw no point in another try (pull #1752 closed)

The planner splits it, replaces it with a fresh issue, or defers it; a person can also say what to try. Nothing starts here until then, and the board lists it.

Deferred behind the Later gate (#595). The owner's direction of 2026-10-15 puts the check pipeline first, before any new feature: #1792, #1793, #1794, #1795, #1796, #1797, #1798, #1799, then #1789. Both tries went red on the flaky N+1 query-count tests that #1799 makes deterministic; it waits for that and for the owner's pipeline order.

replaced by #1805. Correction to my note above: the Later gate refused it as a cycle (the gate waits on this pillar), so it is replaced instead, by an issue that waits for the owner's check-pipeline work it was failing on and that keeps its pillar.