The looks run records performance entries in the browser it already drives and attaches a per-look web-vitals report to the pull's checks, report-only #2983

Replaces the rest of #2942 (#2915 check 9).

Done looks like:

• [ ] src/looks/capture.ts installs a PerformanceObserver before navigation in the browser it already launches, reads the entries after load, and passes them to webvitals(). No Lighthouse, no new dependency, no new Bun.spawn (so test/spawn-pipes.test.ts is untouched).
• [ ] Each look's LCP, CLS and TBT appear with their thresholds in the check summary; nothing fails on them yet.
• [ ] Where no browser is available the report says skipped: no browser and the check stays green.
• [ ] A test feeds recorded entries through the summary and asserts the rendered numbers and thresholds.

Files: src/looks/capture.ts, src/checks/summary.ts, a test. Risk: the capture browser differs per host; the report must tolerate missing entry types.

Parked by the crew: the check failed ("the terminal lays out for the terminal it is in > under the floor, one line says what would help") and the decider saw no point in another try (pull #2988 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 ("the terminal lays out for the terminal it is in > under the floor, one line says what would help") and the decider saw no point in another try (pull #2990 closed).

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

1. the check failed ("the terminal lays out for the terminal it is in > under the floor, one line says what would help") and the decider saw no point in another try (pull #2988 closed)
2. the check failed ("the terminal lays out for the terminal it is in > under the floor, one line says what would help") and the decider saw no point in another try (pull #2990 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.

Split by the planner into #3004 (summary table, pure) and #3005 (capture in the browser, waits for #3004 and #3003). Both attempts failed on test/tui-size.test.ts, which this work never touches and which settles on a timer; #3003 makes it wait for the frame.

Correction to the comment above, whose numbers were wrong: split into #3009 (summary table, pure) and #3010 (capture in the browser, waits for #3009 and #3008). #3008 makes test/tui-size.test.ts wait for the frame instead of a timer.