feat(discover): full reset — clear + rebuild suggestions

POST /api/discover/reset sets discover.resetRequested; the worker, at the
start of the next sweep, clears all PENDING suggestions + contributions +
seed throttles and nulls WatchedArtist.lastDiscoveredAt (keeping
followed/wanted/dismissed decisions), then regenerates everything with current
logic. A 'Reset' button on /discover (2-step confirm) triggers it.

worker 247, web 190 tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/app/api/discover/reset/route.test.ts

@@ -0,0 +1,17 @@
+import { describe, it, expect } from "vitest";
+import { prisma } from "@/lib/db";
+import { POST } from "./route";
+
+describe("POST /api/discover/reset", () => {
+  it("sets the reset + requested flags so the worker rebuilds on the next sweep", async () => {
+    const res = await POST();
+    expect(res.status).toBe(202);
+    expect((await res.json()).reset).toBe(true);
+    const cfg = Object.fromEntries(
+      (await prisma.config.findMany({ where: { key: { in: ["discover.resetRequested", "discover.requested"] } } }))
+        .map((c) => [c.key, c.value]),
+    );
+    expect(cfg["discover.resetRequested"]).toBe("true");
+    expect(cfg["discover.requested"]).toBe("true");
+  });
+});

web/src/app/api/discover/reset/route.ts

@@ -0,0 +1,17 @@
+import { prisma } from "@/lib/db";
+
+// POST /api/discover/reset — request a full rebuild: the worker clears the pending
+// suggestions, contributions, and seed throttles at the start of the next sweep, then
+// regenerates everything with the current logic. Kicks a sweep immediately.
+export async function POST() {
+  await Promise.all(
+    ["discover.resetRequested", "discover.requested"].map((key) =>
+      prisma.config.upsert({
+        where: { key },
+        create: { key, value: "true", secret: false },
+        update: { value: "true" },
+      }),
+    ),
+  );
+  return Response.json({ reset: true }, { status: 202 });
+}

web/src/app/discover/discover-client.tsx

@@ -69,6 +69,7 @@ export function DiscoverClient() {
   const [query, setQuery] = useState("");
   const [search, setSearch] = useState<SearchResult | null>(null);
   const [busy, setBusy] = useState(false);
+  const [confirmReset, setConfirmReset] = useState(false);
   const [followedSimilar, setFollowedSimilar] = useState<Set<string>>(new Set());
   const [albumModal, setAlbumModal] = useState<{ a: Album; artistName: string; artistMbid: string } | null>(null);
 
@@ -106,6 +107,18 @@ export function DiscoverClient() {
     setRunning(true);
   }
 
+  async function resetDiscover() {
+    setConfirmReset(false);
+    const res = await fetch("/api/discover/reset", { method: "POST" }).catch(() => null);
+    if (res && (res.ok || res.status === 202)) {
+      setRows([]); // clears immediately; the rebuild repopulates
+      setRunning(true);
+      toast("Rebuilding suggestions from scratch…");
+    } else {
+      toast("Couldn't reset");
+    }
+  }
+
   async function runSearch(e: React.FormEvent) {
     e.preventDefault();
     if (!query.trim()) return;
@@ -169,13 +182,26 @@ export function DiscoverClient() {
         <button className="btn accent" onClick={discoverNow} disabled={running}>
           {running ? "Discovering…" : "Discover now"}
         </button>
-        <span className="rmeta">
-          {running
-            ? "Sweeping your followed artists for new suggestions…"
-            : lastRunAt
-              ? `Last discovered ${agoLabel(lastRunAt)}${result ? ` · ${result}` : ""}`
-              : "Not yet run — press Discover now to sweep your followed artists"}
-        </span>
+        {confirmReset ? (
+          <>
+            <span className="rmeta">Clear all suggestions and rebuild from scratch?</span>
+            <button className="btn sm accent" onClick={resetDiscover}>Reset</button>
+            <button className="btn sm ghost" onClick={() => setConfirmReset(false)}>Cancel</button>
+          </>
+        ) : (
+          <>
+            <button className="btn sm ghost" onClick={() => setConfirmReset(true)} disabled={running}>
+              Reset
+            </button>
+            <span className="rmeta">
+              {running
+                ? "Sweeping your followed artists for new suggestions…"
+                : lastRunAt
+                  ? `Last discovered ${agoLabel(lastRunAt)}${result ? ` · ${result}` : ""}`
+                  : "Not yet run — press Discover now to sweep your followed artists"}
+            </span>
+          </>
+        )}
       </div>
 
       <SectionHeader title="Find similar" />