fix(lite): always-populated Console (live status) + single-instance log

The Console could look empty if the wallet produced few events. Make it useful
in every state and remove a cross-platform footgun:

- Add a live status header read straight from the controller (connected /
  connecting / disconnected, sync %, and the last open error) — independent of the
  diagnostics event log, so the Console always shows the current connection +
  wallet-open state even when the log is sparse.
- Move LiteDiagnostics::instance() into a single .cpp so there is exactly one
  instance across the binary, rather than relying on the linker folding an
  inline-function static across translation units (a known fragility, especially
  on mingw/Windows — the most likely cause of a stuck-empty event log there).

Verified the writer and reader share one instance on Linux; builds clean for
full-node, lite, and Windows cross-compile; tests pass.

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

src/util/i18n.cpp

@@ -1109,6 +1109,7 @@ void I18n::loadBuiltinEnglish()
         // --- Lite Network tab (server browser) ---
         strings_["lite_console_title"]      = "Console";
         strings_["lite_console_intro"]      = "Diagnostic log: server connections, wallet open/create, and sync events.";
+        strings_["lite_console_status"]     = "Status:";
         strings_["lite_console_clear"]      = "Clear";
         strings_["lite_console_copy"]       = "Copy";
         strings_["lite_console_autoscroll"] = "Auto-scroll";