Introduce src/profile-query/network-summary.ts with the small,
UI-independent building blocks used by every network consumer: interval
union (wall-clock in-flight time), peak concurrency, the long-lived
(long duration, tiny transfer) heuristic, and cache classification.
These are pure functions with no profile dependencies; the callers land
in the following commits.

The summary now leads with the interval-union in-flight wall-clock time
and peak concurrency, computed over all requests intersecting the range.
The phase totals are relabeled "summed across concurrent requests" so
they no longer read as wall-clock time (they previously showed e.g.
"Download: 24m3s" for a 2m28s profile).

Requests still in flight when the recording stopped are now included in
the request list and counted separately ("N request(s) did not complete
during the recording"). Their duration is measured until the end of the
recording, and durations are clamped to the current range so a request
that started before the range does not report more time than the profile
covers.

Requests are now sorted by in-range duration descending by default, with
--sort start to get chronological order back. A limited window (the
default 20 rows) previously showed the first 20 requests chronologically;
agents need the slowest ones. The order is reflected in the header and
exposed as an explicit `sort` field in JSON.

Add a network-activity summary to the two entry-point commands so
wall-clock waiting is as visible as CPU usage. The headline metric is
the interval-union time in flight, plus peak concurrency, in-flight-at-
end counts, and the slowest requests carrying marker handles for
drill-down. Profile-wide numbers are deduped across processes since the
parent process copies every request. The section renders after CPU
activity in both commands.
Extends network-summary.ts with the per-thread and profile-wide
computation on top of the shared helpers, and updates the guide, JSON
schemas, and README so the agent-facing prompt teaches the new signals
(CPU-bound vs wait-bound, the in-flight metric, marker handles, the
long-lived streaming/long-poll annotation, and the --sort flag).

…summaries
Route `collectThreadNetwork` through the `gatherNetworkRecords` /
`clampInterval` / `clampedDurationMs` helpers that `profile info` and
`thread info` already use, and export them from network-summary.ts. This
drops the command's own inline copy of the gather / clamp / count /
cache logic, so there is a single source of truth for "what are this
thread's network requests."