feat(net): invio/ping/download verso Will-Executor in parallelo (anti-freeze)

Problema: i server Will-Executor venivano contattati in sequenza e, su
timeout, send_request riprovava 10x con sleep 3s (~130s per server morto).
Un solo server irraggiungibile bloccava l'intera operazione (impallamento UI).

Soluzione:
- ThreadPoolExecutor: ping e push ora in parallelo (tempo ~= server piu' lento,
  non la somma). Un server morto non blocca piu' gli altri.
- Fast-fail per operazioni interattive (ping/info/download): max_retries=0,
  niente retry-storm.
- Feedback live: callback on_each() aggiorna il dialog server-per-server
  (thread-safe via pyqtSignal di BalWaitingDialog.update).
- Push transazioni: parallelo ma con retry per-server mantenuti (no perdita tx).

File:
- bal/core/willexecutors.py: send_request(+max_retries,+retry_sleep),
  get_info_task fast-fail, NEW ping_servers_parallel(), push_transactions_parallel(),
  DEFAULT_TIMEOUT=5.
- bal/gui/qt/window.py: ping_willexecutors_task + push_transactions_to_willexecutors
  riscritti su helper paralleli con feedback live; fetch_will_executors_list fast-fail.
- bal/core/util.py: BUGFIX get_value_amount usava in_output (bool) invece di
  din_output (tupla) -> TypeError. Scoperto dai test ufficiali Gitea.

Test (contro il codice refactor):
- pytest tests/ ufficiali: 117 core + 65 gui = 182 passed.
- smoke/external_zip/windows_overflow/gui_fixes: OK.
- parallel_ping_test (nuovo): 0.50s per 8 server vs ~4.00s sequenziale.
- ruff: nessun nuovo problema introdotto (codice nuovo PEP8-compliant).

Aggiunti i test ufficiali del repo Gitea + REPORT_NETWORKING_PARALLELO.md.

tests/test_gui_theme.py

@@ -0,0 +1,100 @@
+"""
+Tests for ``bal.gui.qt.theme``.
+
+Covers ``status_color`` priority logic.
+
+Run:
+    QT_QPA_PLATFORM=offscreen python3 tests/test_gui_theme.py
+"""
+
+import sys
+sys.path.insert(0, __file__.rsplit("/", 2)[0])
+
+from bal.gui.qt.theme import status_color
+
+
+# ------------------------------------------------------------------ #
+# Helpers
+# ------------------------------------------------------------------ #
+
+class FakeWillItem:
+    def __init__(self, **status_flags):
+        self._status = dict(status_flags)
+    def get_status(self, name):
+        return self._status.get(name, False)
+
+
+# ------------------------------------------------------------------ #
+# Priority-ordered statuses
+# ------------------------------------------------------------------ #
+
+def test_color_invalidated():
+    assert status_color(FakeWillItem(INVALIDATED=True)) == "#f87838"
+
+
+def test_color_invalidated_overrides_lower():
+    item = FakeWillItem(INVALIDATED=True, PENDING=True, COMPLETE=True)
+    assert status_color(item) == "#f87838"
+
+
+def test_color_replaced():
+    assert status_color(FakeWillItem(REPLACED=True)) == "#ff97e9"
+
+
+def test_color_confirmed():
+    assert status_color(FakeWillItem(CONFIRMED=True)) == "#bfbfbf"
+
+
+def test_color_pending():
+    assert status_color(FakeWillItem(PENDING=True)) == "#ffce30"
+
+
+# ------------------------------------------------------------------ #
+# Branching statuses (CHECK_FAIL / CHECKED / PUSH_FAIL / PUSHED / COMPLETE)
+# ------------------------------------------------------------------ #
+
+def test_color_check_fail_not_checked():
+    item = FakeWillItem(CHECK_FAIL=True)
+    assert status_color(item) == "#e83845"
+
+
+def test_color_check_fail_ignored_if_checked():
+    item = FakeWillItem(CHECK_FAIL=True, CHECKED=True)
+    assert status_color(item) == "#8afa6c"
+
+
+def test_color_checked():
+    assert status_color(FakeWillItem(CHECKED=True)) == "#8afa6c"
+
+
+def test_color_push_fail():
+    assert status_color(FakeWillItem(PUSH_FAIL=True)) == "#e83845"
+
+
+def test_color_pushed():
+    assert status_color(FakeWillItem(PUSHED=True)) == "#73f3c8"
+
+
+def test_color_complete():
+    assert status_color(FakeWillItem(COMPLETE=True)) == "#2bc8ed"
+
+
+def test_color_default():
+    assert status_color(FakeWillItem()) == "#ffffff"
+
+
+def test_color_check_fail_overrides_push_fail():
+    item = FakeWillItem(CHECK_FAIL=True, PUSH_FAIL=True)
+    assert status_color(item) == "#e83845"
+
+
+# ------------------------------------------------------------------ #
+# Main
+# ------------------------------------------------------------------ #
+
+if __name__ == "__main__":
+    for name in sorted(dir()):
+        if name.startswith("test_"):
+            globals()[name]()
+            print(f"  [OK] {name}")
+    print("[OK] All theme tests passed")