feat: Connect to last wifi by default (#752)

## Summary

* **What is the goal of this PR?** 

Use last connected network as default

* **What changes are included?**

- Refactor how an action type of Settings are handled
- Add a new System Settings option → Network
- Add the ability to forget a network in the Network Selection Screen
- Add the ability to Refresh network list
- Save the last connected network SSID
- Use the last connection whenever network is needed (OPDS, Koreader
sync, update etc)

## Additional Context

* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks,
  specific areas to focus on).


![IMG_6504](https://github.com/user-attachments/assets/e48fb013-b5c3-45c0-b284-e183e6fd5a68)

![IMG_6503](https://github.com/user-attachments/assets/78c4b6b6-4e7b-4656-b356-19d65ff6aa12)




https://github.com/user-attachments/assets/95bf34a8-44ce-4279-8cd8-f78524ce745b





---

### AI Usage

Did you use AI tools to help write this code? _** PARTIALLY: I wrote
most of it but I also used Gemini as assist.

---------

Co-authored-by: Eliz Kilic <elizk@google.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/activities/network/WifiSelectionActivity.h

@@ -22,6 +22,7 @@ struct WifiNetworkInfo {
 
 // WiFi selection states
 enum class WifiSelectionState {
+  AUTO_CONNECTING,    // Trying to connect to the last known network
   SCANNING,           // Scanning for networks
   NETWORK_LIST,       // Displaying available networks
   PASSWORD_ENTRY,     // Entering password for selected network
@@ -70,6 +71,12 @@ class WifiSelectionActivity final : public ActivityWithSubactivity {
   // Whether network was connected using a saved password (skip save prompt)
   bool usedSavedPassword = false;
 
+  // Whether to attempt auto-connect on entry
+  const bool allowAutoConnect;
+
+  // Whether we are attempting to auto-connect
+  bool autoConnecting = false;
+
   // Save/forget prompt selection (0 = Yes, 1 = No)
   int savePromptSelection = 0;
   int forgetPromptSelection = 0;
@@ -98,8 +105,10 @@ class WifiSelectionActivity final : public ActivityWithSubactivity {
 
  public:
   explicit WifiSelectionActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
-                                 const std::function<void(bool connected)>& onComplete)
-      : ActivityWithSubactivity("WifiSelection", renderer, mappedInput), onComplete(onComplete) {}
+                                 const std::function<void(bool connected)>& onComplete, bool autoConnect = true)
+      : ActivityWithSubactivity("WifiSelection", renderer, mappedInput),
+        onComplete(onComplete),
+        allowAutoConnect(autoConnect) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;