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/shell/AppShell.test.tsx

@@ -30,8 +30,16 @@ const RESPONSES: Record<string, unknown> = {
 		cached: 0,
 		clients: 0,
 		avg_response_time_us: null,
+		coverage: { complete: true, available_since: 0 },
+	},
+	"/api/stats/timeseries?period=24h": {
+		period: "24h",
+		since: 0,
+		until: 86400,
+		bucket_seconds: 1800,
+		buckets: [],
+		coverage: { complete: true, available_since: 0 },
 	},
-	"/api/stats/timeseries?period=24h": { period: "24h", since: 0, until: 86400, bucket_seconds: 1800, buckets: [] },
 	"/api/health": {
 		status: "ok",
 		disk: { state: "ok", free_bytes: 0, db_bytes: 0, log_bytes: 0, sample_failures: 0 },