Finish the wiring polish: verbosity gate, upload flash, /about links, dead settings slugs

- The Coach verbosity picker is disabled while the concise tone forces
  brief, with a hint saying so, instead of a live control that silently
  does nothing.
- A fresh document upload flashes its new row like the duplicate path
  always did; the settle decision is a pure exported helper with a test.
- /about gains its two inbound links: the /privacy footer and a
  Settings→About credits row (the GeoLite2 EULA wants the attribution
  reachable from the running app).
- The eight settings slugs shadowed by permanent redirects (the seven
  layout children + sharing) leave the slug registry: no more
  prerendering unreachable pages, no dead component wirings, and the
  SectionPlaceholder fallback that could never render is gone. The
  redirects, section components, and layout-hub subpages are unchanged.

src/components/documents/__tests__/use-document-upload-settle.test.ts

@@ -0,0 +1,44 @@
+/**
+ * The upload manager's settle decision (§3.2 + the fresh-upload flash).
+ *
+ * Watched red: with `settleDecision` returning `flashId: null` on the
+ * non-duplicate branch (the pre-v1.37.19 behaviour — only the duplicate
+ * path flashed the row), the fresh-upload case below fails. A fresh upload
+ * used to give no feedback beyond its queue row disappearing.
+ */
+import { describe, expect, it } from "vitest";
+
+import { settleDecision } from "../use-document-upload";
+import type { UploadResult } from "../vault-utils";
+
+function success(duplicate: boolean): UploadResult {
+  return {
+    ok: true,
+    duplicate,
+    document: { id: "doc-1" },
+  } as unknown as UploadResult;
+}
+
+describe("settleDecision", () => {
+  it("flashes the NEW row on a fresh upload (no toast)", () => {
+    expect(settleDecision(success(false))).toEqual({
+      removeFromQueue: true,
+      toastDuplicate: false,
+      flashId: "doc-1",
+    });
+  });
+
+  it("flashes the EXISTING row and toasts on a duplicate", () => {
+    expect(settleDecision(success(true))).toEqual({
+      removeFromQueue: true,
+      toastDuplicate: true,
+      flashId: "doc-1",
+    });
+  });
+
+  it("keeps a failed upload in the queue with no flash", () => {
+    expect(
+      settleDecision({ ok: false, reason: "generic" } as UploadResult),
+    ).toEqual({ removeFromQueue: false, toastDuplicate: false, flashId: null });
+  });
+});

src/components/documents/use-document-upload.ts

@@ -136,6 +136,29 @@ function uploadViaXhr(
   });
 }
 
+/**
+ * The pure settle decision — what a finished upload does to the UI.
+ *
+ * Every success flashes the row (fresh upload → the new row, duplicate →
+ * the existing row); only the duplicate additionally toasts. Exported for
+ * the unit test: until v1.37.19 only the duplicate branch flashed, so a
+ * fresh upload gave no feedback beyond its queue row disappearing.
+ */
+export function settleDecision(result: UploadResult): {
+  removeFromQueue: boolean;
+  toastDuplicate: boolean;
+  flashId: string | null;
+} {
+  if (!result.ok) {
+    return { removeFromQueue: false, toastDuplicate: false, flashId: null };
+  }
+  return {
+    removeFromQueue: true,
+    toastDuplicate: result.duplicate,
+    flashId: result.document.id,
+  };
+}
+
 export interface DocumentUploadManager {
   /** Live queue — uploading entries first-in-first, then error entries. */
   items: UploadQueueItem[];
@@ -196,16 +219,17 @@ export function useDocumentUpload(
 
   const settle = useCallback(
     (localId: string, result: UploadResult) => {
-      if (result.ok) {
-        removeItem(localId);
-        void invalidateKeys(queryClient, [queryKeys.documents()]);
-        if (result.duplicate) {
-          toast.info(t("documents.toast.duplicate"));
-          flashHighlight(result.document.id);
-        }
+      if (!result.ok) {
+        patchItem(localId, { status: "error", failure: result, progress: 0 });
         return;
       }
-      patchItem(localId, { status: "error", failure: result, progress: 0 });
+      const decision = settleDecision(result);
+      removeItem(localId);
+      void invalidateKeys(queryClient, [queryKeys.documents()]);
+      if (decision.toastDuplicate) {
+        toast.info(t("documents.toast.duplicate"));
+      }
+      if (decision.flashId) flashHighlight(decision.flashId);
     },
     [flashHighlight, patchItem, queryClient, removeItem, t],
   );