feat(node): show "node initializing" feedback when the daemon isn't answering yet

When the full-node connect probe (getinfo) times out, the daemon is reachable
at the TCP level but busy initializing (loading the block index, verifying,
activating best chain, …) and won't answer RPC. The wallet only recognized the
JSON-RPC -28 warmup reply, so a raw socket timeout fell through to a bare,
alarming "Connection failed" retry with no indication of what the user was
waiting on.

Add a daemon-initializing UI state that drives the existing loading overlay:

  - WalletState::daemon_initializing — daemon up/launching but not serving yet
    (distinct from warming_up, which needs a -28 reply).
  - App::applyDaemonInitStatus() infers the current phase from the daemon's own
    console output (scanning recent lines for Loading/Verifying/Activating/
    Rescanning/Rewinding/Pruning) and the latest block height, producing a
    friendly title + description, e.g. "Processing blocks… (Block 123456)".
  - The connect loop calls it from the daemon-starting and external-detected
    branches: a timeout -> "reachable but initializing", a connect refusal ->
    "launching, waiting to come online". Cleared on a real connect.
  - The loading overlay now shows the description for daemon_initializing too,
    and the status-bar amber indicator covers it (so Peers/Console tabs without
    the overlay still explain the wait).

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

src/app.h

@@ -701,6 +701,12 @@ private:
     void tryConnect();
     void onConnected();
     void onDisconnected(const std::string& reason);
+    // Set the "node is initializing" UI state (status line + overlay description) from the
+    // embedded/external daemon's launch state and its own console output (current phase + block
+    // height), so a connect probe that times out while the daemon loads shows WHAT it's doing.
+    // `reachableButBusy` is true when the probe connected but got no RPC reply (a timeout),
+    // false when the daemon is merely launching (not bound yet). Returns the status title.
+    std::string applyDaemonInitStatus(bool reachableButBusy);
     // Tear down a connection that died mid-session (daemon crash / restart / dropped
     // socket) so update()'s reconnect branch re-enters tryConnect(). Unlike onDisconnected
     // alone, this also rpc_->disconnect()s so rpc_->isConnected() actually flips to false.