v0.194.0 — one operator email per backup run, and nothing dropped without a trace (R-182)

MEASURED, not supposed. On 2026-08-03 nine per-app recovery_unit_capture_failed
events reached the hub and TWO operator emails went out. The hub's operator
cooldown key is customerID:eventType(+tier) and that event carries `app` but no
`tier`, so the key held no app identifier: the first refused app took the hour's
slot and every other app's failure was discarded BEFORE anything was written
down, leaving no row on any channel.

The obvious fix — put `app` in the key — was ruled against: on a full disk it
produces one email per app, the volume problem wearing the correctness problem's
clothes.

internal/backup/runsummary.go: a per-run collector with exactly admissionSet's
lifetime, fed by all three write legs, emitting backup_run_failures ONCE at the
end and only when something failed. A clean run emits nothing.

The per-app event stays and becomes the RECORD — the hub routes it record-only,
stored and logged every time, never competing for an email slot. The record and
the notification are now different things.

Deliberate skips (disconnected, decommissioned) are excluded: they have their
own alert, and a nightly email about an unplugged drive is one the operator
learns to ignore.

A manual run always reports: the digest carries a unique run_id the cooldown
cannot collapse. Someone pressing the button is actively trying to get a backup.

THE PERIODIC SWEEP GETS A DIGEST TOO. With the per-app event now record-only, a
capture failure found between runs would be recorded and never notified — a new
silence introduced while closing one. That path emits a digest with NO run_id,
so the ordinary 1-hour cooldown caps it exactly as before while the mail now
lists every failing app instead of whichever was first.

A refusal is recorded ONCE, where the verdict is taken, not at the three legs
that consult it — R-181's contract is one verdict per app per run. Noting it per
leg listed one refused app three times and produced "2 of 1 apps failed". Found
by the digest's own test, not in review.

Silence is safe because the hub's deadline check raises expected_backup_missed
from report freshness, independently of any mail this box sends
(monitor/deadline.go:396,417). Confirmed, not assumed.

7 new tests, 4 red-proofs. The main.go seam walk did NOT fail on its first
attempt — the AST test walked the backup package and not main.go; the test was
fixed and the mutation re-run rather than the pass recorded.

controller/internal/api/router.go

@@ -1010,6 +1010,7 @@ func (r *Router) triggerBackup(w http.ResponseWriter, _ *http.Request) {
 	}
 
 	r.logger.Println("[INFO] [api] Manual app-data backup (DB dump) triggered")
+	r.backupMgr.MarkManualRun() // R-182: operator-triggered — its digest must not be collapsed into the nightly one
 	go r.backupMgr.RunDBDumps(context.Background())
 
 	writeJSON(w, http.StatusOK, apiResponse{OK: true, Message: "Mentés elindítva"})