feat(wallet): wallet-files list + switching (P2)

Second phase of multi-wallet: list wallet files and switch the active one.

- Daemon plumbing: EmbeddedDaemon::setWalletFile -> start() passes -wallet=<name>
  (non-default only; skipped during the isolated seed-migration start), and
  DaemonController::syncSettings pushes active_wallet_file on each start.
- App::switchToWallet: persist the new active wallet, then stop + restart the
  node on -wallet=<name> (rescan only if it was never synced in this datadir).
  Reuses the seed-adopt restart coordination; WalletState clears on disconnect
  and the P1 identity-scoped caches re-key, so no previous-wallet data leaks.
  Guarded: full-node, embedded daemon, not mid-restart, no pending send.
- Wallets dialog (Settings -> Backup & Data -> "Wallets…"): a table of wallet
  files (datadir wallet*.dat + user-added folders' *.dat) with size (disk) and
  cached balance / address count / last-opened (wallet index), a current/Active
  badge, Open (switch), and Add folder. Out-of-datadir wallets show "import to
  open" (P3). Added as a sweep surface.
- Mining payout safety: non-destructive warning if the pool-mode worker looks
  like a DragonX address not in the current wallet (stale after a switch).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/mining_tab.cpp

@@ -277,6 +277,23 @@ static void RenderMiningTabContent(App* app)
     RenderMiningModeToggle(app, state, mining, dl, capFont, ovFont, dp, hs, gap, availWidth,
                            s_pool_mode, s_pool_url, s_pool_worker, s_pool_settings_dirty);
 
+    // Payout safety (multi-wallet): in pool mode, warn if the worker looks like a DragonX address
+    // that isn't in the CURRENT wallet — e.g. left over from a wallet you switched away from, so
+    // rewards would land in the wrong wallet. Non-destructive: we only warn, never overwrite (it
+    // could be a deliberate external payout).
+    if (s_pool_mode) {
+        std::string w(s_pool_worker);
+        while (!w.empty() && (w.front()==' '||w.front()=='\t'||w.front()=='\n'||w.front()=='\r')) w.erase(w.begin());
+        while (!w.empty() && (w.back()==' '||w.back()=='\t'||w.back()=='\n'||w.back()=='\r')) w.pop_back();
+        const bool looksLikeAddr = w.size() > 10 && (w.rfind("zs", 0) == 0 || w[0] == 'R');
+        bool inWallet = false;
+        for (const auto& a : state.addresses) if (a.address == w) { inWallet = true; break; }
+        if (looksLikeAddr && !inWallet && !state.addresses.empty()) {
+            ImGui::Dummy(ImVec2(0, gap));
+            Type().textColored(TypeStyle::Caption, Warning(), TR("mining_payout_foreign"));
+        }
+    }
+
     // ================================================================
     // CONTROLS — Glass card with CPU core grid (no heading)
     // ================================================================