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/util/i18n.cpp

@@ -1318,6 +1318,9 @@ void I18n::loadBuiltinEnglish()
         strings_["sb_sapling_not_found"] = "Sapling parameters not found.";
         strings_["sb_daemon_extract_failed"] = "Failed to write daemon files — check free disk space and permissions.";
         strings_["sb_daemon_files_failed"] = "Failed to write daemon files to %s — check free disk space and permissions.";
+        strings_["loading_stall_title"] = "Taking longer than expected";
+        strings_["loading_stall_body"] = "The daemon has been initializing for %.0fs. This can be normal after an update or on first launch (loading the block index or rescanning) — it will connect automatically once ready.";
+        strings_["loading_stall_hint"] = "Still stuck? Open Settings and use Restart Daemon, or check the Console for details.";
         strings_["sb_dragonxd_running"] = "dragonxd running";
         strings_["sb_dragonxd_stopping"] = "Stopping dragonxd...";
         strings_["sb_dragonxd_stopped"] = "dragonxd stopped";