[Ruby184]

What

Four things a run said only as counts are now listed in full and read back:

	on	lists	and reads
--explain unmatched	epg merge, epg build	every programme the merge nearly joined to another source's and did not	the startToleranceMs, windowMs or normalizeTitle that would have joined each group
--explain empty	epg grab, epg build	channel-days a source answered with nothing	a broken parse, a short horizon, a channel another source has, off air, a gap
--explain requests	epg grab, epg build	requests by site and label: count, time out, time queued, failures	where each site's time went, what would change it, what its failures mean
--explain held	epg grab, epg build	sites the source told to slow down	how each hold ended, and the pace that earned it beside the site's rateLimit

--explain can be repeated and writes to stderr once the run is done. It's refused with --dry-run and --format json, and a cancelled run explains nothing.

New on events:

• merge:unmatched (debug), with a signed shiftMs and a why.
• site:done.msBy: the site's wall clock split into source, held, rateLimit, working, queued and other. It's measured as the site runs, including in threads through shared memory.
• RequestCounts.waitedMs.
• pacing:held.retryAfterMs, and lengthened on a hold that was extended.

A reporter may now say which event kinds it wants. The run asks once, the first time it needs to. It then makes its frequent events only where one is wanted: entry:*, request:started/done, site:note, pacing:rateLimit and merge:unmatched. A site in a thread neither makes nor sends them.

• The shipped reporters want what they show or count.
• emitterReporter wants what its emitter has listeners for, or what { wants } says.
• combineReporters wants what any of its reporters wants.
• A config's events may now be a reporter, for an emitter that hears more than its listeners do.

Also:

• merge:summary.combined no longer counts a source joining its own programme held over from the day before.
• nearMiss counts only another source's programmes left unjoined.
• A reporter given an event of a kind this version doesn't know filters it by the event's own level instead of throwing.

Breaking changes

• ResolvedMatch.matches(a, b) is replaced by apart(a, b), which returns why two programmes are not one broadcast, or undefined when they are.
• site:done.msBy and RequestCounts.waitedMs are required.
• Emit carries a required hears set. Make one with emitter({ reporter }); sitePacing throws at the call on a plain function.
• A run no longer makes its frequent events for kinds an emitterReporter's emitter has no listener for. An emitter whose own emit passes every event on needs { wants: () => true }.

Measured

Plain Node on the built dist, 1000 channels × 7 days, one request per channel-day, text reporter at info:

• Skipping unwanted events: 675 → 625ms in-process (−7%), and 1990 → 1910ms in one thread (−4%).
• The site clock: about 4µs per channel-day at concurrency 1 in the worst case. All four explanations together: about 2µs per channel-day.
• A simpler near-miss pass (one scan after placement) gave the same answers but ran about 60% slower where retitled programmes sit inside the match window, so the current design stays.

Checks

Format, lint, typecheck and build are clean. Tests: 2329 passed, 2 skipped, on Node 22.18, 24.15 and 26.12.