[tmm]

tmm's decision 3(b): a typed live view, the Rust counterpart of Swift's LiveQuery (useQuery). GPUI and Rune move onto it and their copies are deleted.

let issues: LiveView<Vec<Issue>> = zero.live(&ISSUE_LIST_V2.with(args), &ttl)?;
issues.value();          // Rc<Vec<Issue>>
issues.result_type();
issues.error();          // Option<LiveError>: Query(..) or Decode(..), keeping the last good value
let remove = issues.add_listener(|rows, result_type| { /* ... */ });

• Zero::live takes a typed Query<R, T> (default build) or a QueryRequest (serde feature), through a small typed::TypedQuery<C> trait.
• It keeps working when Zero replaces its client; a test covers this through the public API.
• Row reuse, as Swift's RowCache does: an update re-reads only the rows whose entries changed, and an update with no row changes reads nothing. QueryValue gains update_from_view, with a default.

Benchmarks (3 rounds, medians): an optimistic update with the view read as structs, by hand vs LiveView. Making the view costs the same either way, and the existing benchmarks against main are within noise.

Rows	By hand	LiveView
1,000	82.8 µs	19.1 µs
10,000	759 µs	61.6 µs
100,000	13.1 ms	0.52 ms

Apps:

• GPUI: Live is now LiveView plus its cx.notify wake-up.
• Rune: watch builds a LiveView per client.

Slots and error display are unchanged. One difference: rows that fail to decode on the first read now make live fail, and the app prints the error. That only happens when the generated types don't match the data, which is a bug.

Changeset: zero-rust minor (with 0.3.0).

Checked locally:

• Rust: clippy -D warnings, tests (11 new in live_view.rs), docs, and conformance (66,384 cases, 0 failures). The default build still has no dependencies.
• Apps: zbugs-model, zbugs-gpui (with and without e2e), and zbugs-rune pass fmt, clippy, and tests.