Make a starved discovery cycle say so, in the log and on /api/health.

For about a year the production RELAYS list did not include the relay carrying
the kind 38000/38172 archive. Every backfill read about thirty events, wrote them
faithfully, reported ok=true, and the nightly build republished an index of eight
mints. Nothing measured the difference between "the cycle completed" and "the
cycle read anything", so nothing went red.

Three signals now do:

  - Per-relay attribution. queryRelays() replaces pool.querySync(), which merges
    every relay into one deduplicated array and throws away who sent what. It
    keeps one subscription per relay over the pool's existing sockets and shares
    a single alreadyHaveEvent across them, so an event five relays carry is still
    verified once; receivedEvent fires before that check, which is what makes the
    per-relay count mean "what this relay contributed". The deadline moved out of
    each Subscription's own EOSE timer so `eose` means a frame arrived rather than
    something timed out.

  - A WARN naming any relay that will not connect, on every cycle, and any relay
    that connected and sent nothing, on backfills only. An incremental cycle is
    supposed to come back empty.

  - BACKFILL_MIN_EVENTS, default 200. Under it, ERROR discovery starvation
    suspected and a flag health reports as discovery_starved, forcing 503. Sticky
    across incremental cycles so an hourly cycle finding four events cannot clear
    what a backfill diagnosed; stored in the database so a restart cannot either.

A fresh database is starved until its first backfill lands. That is intended: it
holds the build's health gate rather than publishing a site made from nothing.

Verified against the live relay set — 1528 events, five relays connected, EOSE on
all five, health 200 — and against an unreachable list, which produces the two
WARN lines, the ERROR, and 503.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

shared/src/types.ts

@@ -236,6 +236,29 @@ export interface Stats {
   lnurl_reviews: number;
 }
 
+/**
+ * How one configured relay answered during the last discovery cycle.
+ *
+ * The three facts are deliberately separate, because the failure this exists to catch
+ * had all three looking different from each other: the relays in `RELAYS` connected
+ * fine, reached EOSE fine, and simply did not carry the archive, so `events` was the
+ * only field that would have said anything. A relay that is down and a relay that is
+ * up and empty are different problems with different fixes.
+ */
+export interface RelayHealth {
+  url: string;
+  /** A socket was opened to it. false means the address is wrong or the relay is down. */
+  connected: boolean;
+  /**
+   * Events it sent, counted before cross-relay deduplication — so this is what *this*
+   * relay contributed, not what was new because of it. Zero on a connected relay is
+   * the interesting number.
+   */
+  events: number;
+  /** Every query it was asked ended in a real EOSE rather than in a timeout. */
+  eose: boolean;
+}
+
 /** `GET /api/health`. */
 export interface Health {
   status: 'ok' | 'degraded';
@@ -244,6 +267,26 @@ export interface Health {
   last_discovery_at: number | null;
   mints_tracked: number;
   updated_at: number;
+  /**
+   * Per-relay outcome of the last discovery cycle. Empty until one has run — including
+   * on a fresh database, which is why a brand new deployment reports degraded until its
+   * first backfill finishes.
+   */
+  discovery_relays: RelayHealth[];
+  /** Unique events the last discovery cycle received. null before the first one. */
+  last_discovery_events: number | null;
+  /** Which kind of cycle those numbers describe. */
+  last_discovery_mode: 'backfill' | 'incremental' | null;
+  /**
+   * The last backfill came back under `backfill_min_events`, or none has run yet.
+   *
+   * This is the flag that would have caught a year of ~31-event backfills against a
+   * relay list missing the archive. It forces `status` to degraded, and /api/health to
+   * 503, which is what the build gate and the site's own health checks read.
+   */
+  discovery_starved: boolean;
+  /** `BACKFILL_MIN_EVENTS`, echoed so a reader of this payload can see the threshold. */
+  backfill_min_events: number;
 }
 
 /**