refactor(audit): batch 8 — share the post-encrypt daemon-restart block

Extract App::restartDaemonAfterEncryption(taskName, announceRestartStatus)
from the two verbatim copies in encryptWalletWithPassphrase and
processDeferredEncryption. The two differed only in the async task name and
whether they set connection_status_ = "restarting_after_encryption" first
(the immediate encrypt path does; the deferred path does not) — both
parameterized. The 20x100ms settle loop, cancel/shutdown guards, and
stop/startEmbeddedDaemon sequence are preserved exactly.

Deliberately NOT done: the audit's "decrypt 5-deep callback pyramid" finding.
On inspection the nesting is load-bearing, not gratuitous — WalletSecurityWorkflow
is unsynchronized main-thread-only state, and each step's worker->MainCb bounce
is what keeps its mutations on the main thread (the UI reads snapshot()/importActive()
every frame); collapsing the pipeline onto one worker/async task would race the
UI, and the final restart+import stage requires an AsyncTaskManager::Token that
worker_->post can't supply. Left byte-for-byte intact.

Full-node + Lite build clean; ctest 1/1 (incl. WalletSecurity controller tests);
hygiene clean.

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

src/app.h

@@ -395,6 +395,12 @@ public:
 
     // Wallet encryption helpers
     void encryptWalletWithPassphrase(const std::string& passphrase);
+    // Post-encrypt daemon restart: the daemon shuts itself down after
+    // encryptwallet, so restart it off the main thread. Shared by the
+    // immediate and deferred encryption continuations. When
+    // announceRestartStatus is true, connection_status_ is updated first so
+    // the loading overlay explains the restart.
+    void restartDaemonAfterEncryption(const char* taskName, bool announceRestartStatus);
     void unlockWallet(const std::string& passphrase, int timeout);
     void lockWallet();
     void changePassphrase(const std::string& oldPass, const std::string& newPass);