fix: dedup fund_capture alerts for same-date sibling records and add clear-all

fund_capture alerts for a symbol with multiple capture records sharing one
as_of re-fired every batch cycle: the single comparison-state slot
ping-ponged between sibling evidence URLs, and the pre-check dedup key
never matched the stored buildDedupKey format. Track a seen-set of URLs in
comparison state and align dedup-key construction with buildDedupKey.
Also add alerts.clearAll (hard delete) with an immediate-refresh bell.

app/src/lib/trpc.ts

@@ -1247,6 +1247,7 @@ export const api = {
     acknowledge: (alertId: string) => trpcMutate<{ ok: boolean }>("alerts.acknowledge", { alertId }),
     unackedCount: () => trpcQuery<{ count: number }>("alerts.unackedCount"),
     acknowledgeAll: () => trpcMutate<{ ok: boolean }>("alerts.acknowledgeAll", {}),
+    clearAll: () => trpcMutate<{ ok: boolean }>("alerts.clearAll", {}),
     createSubscription: (input: { alertType: string; watchlistId?: string; symbol?: string; params?: string }) =>
       trpcMutate<AlertSubscriptionRow>("alerts.createSubscription", input),
     listSubscriptions: (symbol?: string) =>