fix(network): show live signal strength and classify auth failures (#312)

# Description
- [x] Bug fix

Stacked on #311, review after it merges. Last PR in the #306 split.

Live Wi-Fi signal strength and auth-failure classification.

- `_active_ap_signal`, `_signal_map_once`, `_read_connectivity`,
`_is_wifi_ap_mode`
- `_classify_settings_error`; `_validate_psk` follows NM's own psk rule
(length in bytes, SAE exempt) and runs before the old profile is backed
up
- `_wait_for_connection` stops early when the Wi-Fi device reports
FAILED (the StateChanged listener counts it, since NM leaves FAILED too
fast for polling to see it)
- Connection waits read the Wi-Fi interface's own IP, so an ethernet or
VPN primary link can't fake success
- `_async_get_network_password` prefills the saved-network password
field; saved page shows the static IP/mask
- `networkWindow.py` operation-result routing (success/failure/timeout
handlers); the hotspot page's activate drops ethernet like the toggle
does
- `test_network_ui.py`, `test_worker_unit.py`,
`test_worker_helpers_unit.py` coverage

Author: gmmcosta15

BlocksScreen/lib/network/manager.py

@@ -43,6 +43,7 @@ class NetworkManager(QObject):
     error_occurred = pyqtSignal(str, str)
     reconnect_complete = pyqtSignal()
     hotspot_config_updated = pyqtSignal(str, str, str)
+    network_password_loaded = pyqtSignal(str, str)
 
     def __init__(self, parent: QObject | None = None) -> None:
         """Create the worker, wire all signals"""
@@ -72,6 +73,7 @@ def __init__(self, parent: QObject | None = None) -> None:
         self._worker.error_occurred.connect(self.error_occurred)
         self._worker.hotspot_info_ready.connect(self._on_hotspot_info_ready)
         self._worker.reconnect_complete.connect(self.reconnect_complete)
+        self._worker.network_password_loaded.connect(self.network_password_loaded)
         self._worker.initialized.connect(self._on_worker_initialized)
 
         # Keepalive timer: safety net for any missed D-Bus signals.
@@ -170,9 +172,11 @@ def _on_networks_scanned(self, networks: list) -> None:
 
     @pyqtSlot(list)
     def _on_saved_networks_loaded(self, networks: list) -> None:
-        """Cache saved profiles, rebuild lowercase lookup map, and re-emit."""
+        """Cache saved profiles, rebuild lowercase lookup map, and re-emit if changed."""
         if self._shutting_down:
             return
+        if networks == self._cached_saved:
+            return
         self._cached_saved = networks
         self._saved_network_map = {n.ssid.lower(): n for n in networks}
         self.saved_networks_loaded.emit(networks)
@@ -249,6 +253,10 @@ def update_network(  # nosec B107
         """Update the password and/or autoconnect priority for a saved profile."""
         self._schedule(self._worker._async_update_network(ssid, password, priority))
 
+    def get_network_password(self, ssid: str) -> None:
+        """Ask NM for a saved profile's psk; answered by network_password_loaded."""
+        self._schedule(self._worker._async_get_network_password(ssid))
+
     def set_wifi_enabled(self, enabled: bool) -> None:
         """Enable or disable the Wi-Fi radio."""
         self._schedule(self._worker._async_set_wifi_enabled(enabled))

BlocksScreen/lib/network/models.py

@@ -237,7 +237,7 @@ class SavedNetwork:
     signal_strength: int = 0
     timestamp: int = 0  # Unix time of last successful activation
     is_dhcp: bool = True  # True = auto (DHCP), False = manual (static IP)
-    ip_address: str = ""
+    ip_address: str = ""  # static IPv4 config, all empty while on DHCP
     netmask: str = ""
     gateway: str = ""
     dns_servers: tuple[str, ...] = ()