fix: Tier-2 UX robustness — action guards, in-progress guards, input trimming

The app-wide "import-key pattern" fixes (missing guards / untrimmed input / no
re-entrancy protection), from the robustness audit:

- Import-key dialog: unify the type indicator and the RPC dispatch on one
  classifier (classifyPrivateKey is now prefix-aware — an "SK..." shielded key no
  longer misroutes to the transparent RPC), trim manual input (not just Paste),
  and gate both the indicator and the Import button on a shared
  isRecognizedPrivateKey() so unrecognized/empty input can't be submitted.
- Shield: guard the submit button on connected + !syncing (like Send), with a
  disabled tooltip, instead of firing into a raw daemon error.
- Mining: disable the pool Mine button when the payout address is empty
  ("enter a payout address first"), and trim the pool URL/worker on persist.
- Console: track in-flight RPC commands (atomic counter + busy() override) so the
  input is disabled while a command runs instead of piling up on the worker.
- Maintenance (rescan/repair/delete-chain/reinstall-daemon): re-entrancy guard —
  bail with "already in progress" instead of launching a duplicate destructive op.
- Bootstrap dialog: re-attach to an in-flight download on reopen instead of
  resetting state and orphaning the running worker.

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

src/ui/windows/console_command_executor.h

@@ -12,6 +12,7 @@
 #include "console_channel.h"
 #include "imgui.h"
 
+#include <atomic>
 #include <cstdint>
 #include <deque>
 #include <functional>
@@ -91,9 +92,12 @@ public:
     ConsoleLogFilterCaps logFilterCaps() const override { return {true, true, true, true}; }
     void printHelp(const ConsoleAddLineFn& add) override;
     ConsoleStatusLine toolbarStatus() const override;
+    // A command is in flight on the RPC worker — lets the UI disable the input (no queued pile-up).
+    bool busy() const override { return in_flight_.load() > 0; }
 
 private:
     App*   app_;
+    std::atomic<int> in_flight_{0};
     size_t last_daemon_output_size_ = 0;
     size_t last_xmrig_output_size_  = 0;
     int    last_daemon_state_       = -1;  // daemon::EmbeddedDaemon::State as int