Phase 5: secondary screens (diagnostics, skills, training)

Port the remaining read views from the vanilla UI to Next.js:

- /diagnostics — system health snapshot (DB connected, table counts,
  active tasks, failed and stuck documents). Uses the existing
  /api/system/diagnostics payload with a 10s refetchInterval so the
  page self-updates while the user watches.
- /skills — Paperclip skill inventory with sync status (DB-only,
  disk-only, synced, not-synced) as a card grid driven by
  /api/admin/skills.
- /training — Dafna's style portrait as three tabs on one page:
  * Report: corpus KPIs + CSS conic-gradient subject donut
    (SubjectDonut ported from index.html renderHero) + horizontal
    anatomy bars + top-12 signature phrases.
  * Corpus: TanStack Table of style_corpus rows with an inline
    delete mutation (useDeleteCorpusEntry invalidates both the
    corpus list and the style report so KPIs update).
  * Compare: two-decision selector backed by /api/training/compare,
    side-by-side panels plus shared / only-A / only-B pattern
    lists.

New API modules: lib/api/system.ts, lib/api/skills.ts,
lib/api/training.ts. All three use TanStack Query with staleTime
profiles tuned per endpoint (10s for diagnostics, 30s for skills,
60s for training reports).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web-ui/src/lib/api/training.ts

@@ -0,0 +1,151 @@
+/**
+ * Training / style corpus hooks.
+ *
+ * Endpoints touched (all under /api/training/):
+ *   - GET /style-report → the dashboard payload (corpus stats + anatomy
+ *     + signature phrases + per-decision contribution)
+ *   - GET /corpus → flat list of decisions for the corpus tab / compare tool
+ *   - GET /compare?a=UUID&b=UUID → side-by-side comparison
+ *   - DELETE /corpus/{id} → remove a decision from the corpus
+ */
+
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { apiRequest } from "./client";
+
+export type StyleReport = {
+  corpus: {
+    decision_count: number;
+    total_chars: number;
+    avg_chars: number;
+    date_range: [string | null, string | null];
+    decisions: Array<{
+      number: string;
+      date: string;
+      chars: number;
+      subjects: string[];
+    }>;
+    subject_distribution: Array<{ label: string; count: number }>;
+    headline: string;
+  };
+  anatomy: {
+    sections: Array<{
+      type: string;
+      label: string;
+      avg_chars: number;
+      pct: number;
+      coverage: number;
+    }>;
+    total_coverage: number;
+    headline: string;
+  };
+  signature_phrases: {
+    items: Array<{
+      type: string;
+      text: string;
+      context: string;
+      frequency: number;
+      examples: string[];
+    }>;
+    total_decisions: number;
+    top_display: string;
+    headline: string;
+  };
+  contribution: {
+    growth_curve: Array<{
+      decision_number: string;
+      date: string;
+      cumulative: number;
+    }>;
+    decision_contributions: unknown[];
+    total_patterns: number;
+    headline: string;
+  };
+};
+
+export type CorpusDecision = {
+  id: string;
+  decision_number: string;
+  decision_date: string;
+  subject_categories: string[];
+  chars: number;
+  created_at: string;
+};
+
+export type CompareResult = {
+  a: CompareSide;
+  b: CompareSide;
+  shared: PatternEntry[];
+  only_a: PatternEntry[];
+  only_b: PatternEntry[];
+};
+
+export type CompareSide = {
+  id: string;
+  decision_number: string;
+  decision_date: string;
+  chars: number;
+  subjects: string[];
+  sections: Array<{ type: string; chars: number }>;
+  patterns_count: number;
+};
+
+export type PatternEntry = {
+  id: string;
+  type: string;
+  text: string;
+  context: string;
+};
+
+export const trainingKeys = {
+  all: ["training"] as const,
+  report: () => [...trainingKeys.all, "style-report"] as const,
+  corpus: () => [...trainingKeys.all, "corpus"] as const,
+  compare: (a: string, b: string) =>
+    [...trainingKeys.all, "compare", a, b] as const,
+};
+
+export function useStyleReport() {
+  return useQuery({
+    queryKey: trainingKeys.report(),
+    queryFn: ({ signal }) =>
+      apiRequest<StyleReport>("/api/training/style-report", { signal }),
+    staleTime: 60_000,
+  });
+}
+
+export function useCorpus() {
+  return useQuery({
+    queryKey: trainingKeys.corpus(),
+    queryFn: ({ signal }) =>
+      apiRequest<CorpusDecision[]>("/api/training/corpus", { signal }),
+    staleTime: 60_000,
+  });
+}
+
+export function useCompare(a: string | null, b: string | null) {
+  return useQuery({
+    queryKey: trainingKeys.compare(a ?? "", b ?? ""),
+    queryFn: ({ signal }) =>
+      apiRequest<CompareResult>(
+        `/api/training/compare?a=${encodeURIComponent(a!)}&b=${encodeURIComponent(b!)}`,
+        { signal },
+      ),
+    enabled: Boolean(a && b && a !== b),
+    staleTime: Infinity,
+  });
+}
+
+export function useDeleteCorpusEntry() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (id: string) =>
+      apiRequest<{ deleted: boolean }>(
+        `/api/training/corpus/${encodeURIComponent(id)}`,
+        { method: "DELETE" },
+      ),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: trainingKeys.corpus() });
+      qc.invalidateQueries({ queryKey: trainingKeys.report() });
+    },
+  });
+}