milestone 28: query provenance — every logged query is exactly explainable

query rows gain qclass, rcode, group, policy action and reason, the
matched rule or list entry with its source, cname and safe-search
targets, route kind, forward zone, and the resolver that actually
answered — the pool and local markers die. servfails are logged and
name the resolver that lost; post-parse protocol refusals become rows.
a detail page at /queries/:id renders the ordered explanation, and
coverage watermarks distinguish an empty history from a missing one.

the schema fingerprint changes: existing query history is recreated
with the old file kept aside and the reset filed as a resolved
diagnostic. fixes an oversized udp reply being rebuilt as noerror,
which handed clients a truncated nxdomain as success.

admin/src/features/clients/clientNames.tsx

@@ -37,17 +37,27 @@ export function useClientNames(): ClientNames {
 	);
 }
 
-export function ClientName({ ip, names }: { ip: string; names: ClientNames }) {
+/**
+ * The name the loaded list gives this address right now, or null when it gives
+ * none. Callers that must distinguish "named" from "bare address" — rather than
+ * just render whichever applies — read this instead of re-deriving precedence.
+ */
+export function clientLabel(ip: string, names: ClientNames): { text: string; learned: boolean } | null {
 	const client = names.get(ip);
-	if (client === undefined || (client.name === "" && client.learned_name === "")) {
-		return <span {...stylex.props(shared.mono)}>{ip}</span>;
-	}
+	if (client === undefined) return null;
+	if (client.name !== "") return { text: client.name, learned: false };
+	if (client.learned_name !== "") return { text: client.learned_name, learned: true };
+	return null;
+}
+
+export function ClientName({ ip, names }: { ip: string; names: ClientNames }) {
+	const label = clientLabel(ip, names);
+	if (label === null) return <span {...stylex.props(shared.mono)}>{ip}</span>;
 	// The name replaces the address on screen, so the address stays reachable
 	// as the tooltip rather than disappearing from the row entirely.
-	if (client.name !== "") return <span title={ip}>{client.name}</span>;
 	return (
-		<span title={ip} {...stylex.props(shared.learnedName)}>
-			{client.learned_name}
+		<span title={ip} {...stylex.props(label.learned && shared.learnedName)}>
+			{label.text}
 		</span>
 	);
 }