fix(startup): surface a "taking too long" notice when the daemon won't come up

F3: the daemon connect loop retried forever with only an animated spinner when the
daemon was reachable-but-never-ready (stuck in RPC warmup / -28, or an external daemon
that never finishes init) -- no error, no guidance, no escape. It now stamps
connect_stall_since_ the moment the daemon first goes "reachable but not ready" (the
warmup branch + applyDaemonInitStatus) and clears it on connect / disconnect /
warmup-complete. A pure, unit-testable util::connectHasStalled() helper (new
util/connect_stall.h, 45s default from ui.toml [screens.loading].stall-timeout-sec)
drives a "Taking longer than expected" notice in renderLoadingOverlay(): a title, a
reassuring body with elapsed seconds, and a full-node hint to Settings > Restart Daemon
or the Console. The background retry keeps running underneath, so the notice self-clears
the instant it connects. Guarded off while the daemon is in State::Error (that case is
owned by the existing crash-count hint).

The overlay is a pure draw-list layer with no interactive widgets, so this follows the
existing crash-hint idiom (guidance text, not injected buttons); the stalled state is
computed locally in the overlay, so the only new App member is connect_stall_since_.

Adds testConnectHasStalled to test_phase4.cpp and three i18n keys to i18n.cpp (English
source of truth; the res/lang/*.json back-fill is deferred to a single
add_missing_translations.py run at the end of the batch).

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

src/app.h

@@ -1023,6 +1023,7 @@ private:
     std::uint64_t clipboard_secret_hash_ = 0;
     double clipboard_clear_deadline_ = 0.0;
     float loading_timer_ = 0.0f;  // spinner animation for loading overlay
+    double connect_stall_since_ = 0.0;  // ImGui::GetTime() when the daemon first went "reachable but not ready"; 0 = not stalling (see util/connect_stall.h)
 
     // Current page (sidebar navigation)
     ui::NavPage current_page_ = ui::NavPage::Overview;