feat(fullnode): manage the daemon binary in Settings; stop auto-overwriting it

Previously the wallet re-extracted the bundled dragonxd on startup whenever the
installed binary's size differed from the bundle ("stale" overwrite), which could
replace a node a user had deliberately placed in dragonx/.

Now dragonx binaries (dragonxd/cli/tx) are auto-placed ONLY when missing — never
auto-overwritten on a size mismatch (needsParamsExtraction + extractEmbeddedResources).
Params/asmap keep their size-based refresh; a daemon dropped next to the wallet exe
still takes priority and is never touched.

Replacing the daemon is now an explicit action: Settings → "Daemon binary" reports the
installed binary's version (scanned from the file), size and modified date, compares it
to the version bundled in this build, and offers an "Install bundled daemon" button.
That stops the node, overwrites dragonxd/cli/tx with the bundled copies (waiting for the
process to release the file lock), and restarts — wallet/keys/chain data untouched.

Adds resources::{getInstalledDaemonInfo,getBundledDaemonInfo,reextractBundledDaemon}
(+ a version-string scanner) and App::reinstallBundledDaemon().

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app.h

@@ -307,6 +307,7 @@ public:
     void setUseEmbeddedDaemon(bool use) { use_embedded_daemon_ = use && supportsEmbeddedDaemon(); }
     void rescanBlockchain();  // restart daemon with -rescan flag
     void repairWallet();  // restart daemon with -zapwallettxes=2 (wipe & rebuild wallet tx records)
+    void reinstallBundledDaemon();  // stop daemon, overwrite installed binary with the bundled one, restart
     void deleteBlockchainData();  // stop daemon, delete chain data, restart fresh
     bool stopDaemonForBootstrap(); // stop daemon + disconnect for bootstrap, returns true if was running
     bool isBootstrapDownloading() const { return bootstrap_downloading_; }