feat: PostW5 Wave B2 — share-reports moderation queue

Closes audit v2 §05 ("Reports queue"). Migration 0027 landed earlier
in 52c454e; this commit ships the consumer surface end-to-end.

Backend
- New `share_reports` module: ShareReport/ShareReportStatus/
  ShareReportReason + ShareReportStore trait + Postgres impl +
  MemoryShareReportStore for tests.
- `POST /v1/share/report` in sharing_routes: reporter (auth'd user)
  must be one of {owner, recipient}; rate-limited at 5 reports per
  reporter per 24h; emits `share.reported` audit row.
- `GET /v1/admin/sharing/reports?status=` and
  `POST /v1/admin/sharing/reports/:id/resolve` in admin_sharing_routes:
  moderator-gated (admins inherit); resolve emits
  `share.report_resolved` audit row; 409 on double-resolve.
- main.rs wires `Arc<dyn ShareReportStore>` extension.
- openapi.rs registers 3 paths + 5 schemas.
- 8 new store tests (status/reason round-trips, is_resolution,
  create+get, list+filter+order, double-resolve rejection, not_found,
  case-insensitive rate-limit count). Suite 289 → 297 passing.

Frontend
- `apps/web/src/app/sharing/actions.ts` — `reportShareAction`
  server action.
- `/sharing` (inbound list): per-share collapsed `<details>` with a
  reason picker + optional details textarea + Submit button. Form
  posts to the new action; recipient_handle is threaded from
  `session.claimedHandle` (server-side, not trusted from client).
- `/admin/sharing/reports` (NEW): moderator queue page with status
  filter strip (open/dismissed/share_revoked/user_suspended/all),
  per-row form with three resolution buttons (Dismiss / Revoke /
  Suspend owner), optional moderator note (≤ 500 chars). Server
  action revalidates the path on each transition; 409 races refresh
  silently rather than throwing.
- `/admin/sharing` overview grows a "Reports queue →" link in the
  existing sub-nav strip.
- api.ts client functions: `reportShare`, `getAdminSharingReports`,
  `resolveShareReport` + 5 schema type aliases.
- schema.ts regenerated.

All gates green: cargo check, cargo test (297/297), cargo clippy
-D warnings, cargo fmt --check, pnpm typecheck, pnpm lint
(only pre-existing warnings).

Author: Nigel Tatschner

apps/web/src/app/admin/sharing/page.tsx

@@ -371,6 +371,13 @@ export default async function AdminSharingOverviewPage() {
         >
           Sharing audit log →
         </Link>
+        <Link
+          href={'/admin/sharing/reports' as Route}
+          className="ss-btn ss-btn--ghost"
+          style={{ textDecoration: 'none' }}
+        >
+          Reports queue →
+        </Link>
       </nav>
     </div>
   );

apps/web/src/app/admin/sharing/reports/actions.ts

@@ -0,0 +1,63 @@
+'use server';
+
+/**
+ * Server actions for the share-reports moderation queue
+ * (audit v2 §05). One action per moderator transition; each one
+ * wraps the `/v1/admin/sharing/reports/:id/resolve` POST, then
+ * revalidates the queue path so the next render reflects the new
+ * state.
+ *
+ * Error handling matches the rest of the admin surface: 401 sends
+ * the user to login (with `next` set so they land back on the
+ * queue), 403 boots them to the dashboard, 409 is the "someone
+ * else got there first" race and falls through to a soft refresh,
+ * anything else re-throws so the page boundary catches it.
+ */
+
+import { revalidatePath } from 'next/cache';
+import { redirect } from 'next/navigation';
+import { ApiCallError, resolveShareReport } from '@/lib/api';
+import { getSession } from '@/lib/session';
+
+const LOGIN_NEXT = '/auth/login?next=/admin/sharing/reports';
+const QUEUE_PATH = '/admin/sharing/reports';
+
+/**
+ * `outcome` is supplied by the form via a hidden input, so each
+ * resolution button (`Dismiss` / `Revoke share` / `Suspend owner`)
+ * posts a different value to the same action.
+ */
+export async function resolveShareReportAction(
+  formData: FormData,
+): Promise<void> {
+  const session = await getSession();
+  if (!session) redirect(LOGIN_NEXT);
+
+  const id = String(formData.get('id') ?? '').trim();
+  const outcome = String(formData.get('outcome') ?? '').trim();
+  const noteRaw = formData.get('note');
+  const note =
+    typeof noteRaw === 'string' && noteRaw.trim().length > 0
+      ? noteRaw.trim()
+      : undefined;
+
+  if (!id || !outcome) {
+    revalidatePath(QUEUE_PATH);
+    return;
+  }
+
+  try {
+    await resolveShareReport(session.token, id, { outcome, note });
+  } catch (e) {
+    if (e instanceof ApiCallError) {
+      if (e.status === 401) redirect(LOGIN_NEXT);
+      if (e.status === 403) redirect('/dashboard');
+      if (e.status === 409) {
+        revalidatePath(QUEUE_PATH);
+        return;
+      }
+    }
+    throw e;
+  }
+  revalidatePath(QUEUE_PATH);
+}