feat: Phase 4 - Connection Management

Implemented complete Wi-Fi connection flow with authentication.

Phase 4: Connection Management
- Created passphrase authentication dialog (ui/wifi_auth.c)
- Network selection handler in popup
- Integrated agent with passphrase dialog
- Complete connection flow: select network → auth dialog → agent → iwd
- Support for open and secured (WPA2/WPA3) networks
- Proper async D-Bus message handling in agent

Features:
- Passphrase dialog with password entry widget
- Minimum 8-character passphrase validation
- Network selection from popup (click to connect)
- Open networks connect directly without dialog
- Secured networks (psk, 8021x) show auth dialog
- Agent stores pending D-Bus message for async reply
- Passphrase sent securely to iwd via D-Bus
- Memory cleared after passphrase transmission
- Cancel button sends proper error reply to iwd
- Network type detection (open/psk/8021x)

Connection Flow:
1. User clicks network in popup
2. Check security type
3. If open: connect directly
4. If secured: show passphrase dialog
5. User enters passphrase
6. Agent receives RequestPassphrase from iwd
7. Dialog shows for network
8. User clicks Connect
9. Agent sends passphrase to iwd
10. iwd handles connection

Agent Improvements:
- Stores pending D-Bus message for async reply
- Properly returns NULL to indicate async handling
- Sends passphrase via eldbus_message_method_return_new
- Cancellation sends error reply to iwd
- Integrates with UI dialog system

Module size: 191KB (increased from 152KB)
Total lines: ~2,900 across 20 files

Next phase: Advanced Features (hidden networks, multiple adapters, error handling)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/iwd/iwd_agent.c

@@ -126,26 +126,64 @@ iwd_agent_shutdown(void)
    iwd_agent = NULL;
 }
 
-/* Set passphrase for pending request */
+/* Set passphrase for pending request and send reply */
 void
 iwd_agent_set_passphrase(const char *passphrase)
 {
-   if (!iwd_agent) return;
+   Eldbus_Message *reply;
 
-   eina_stringshare_replace(&iwd_agent->pending_passphrase, passphrase);
-   DBG("Passphrase set for pending request");
+   if (!iwd_agent) return;
+   if (!iwd_agent->pending_msg)
+   {
+      WRN("No pending passphrase request");
+      return;
+   }
+
+   DBG("Sending passphrase to iwd");
+
+   /* Create reply message */
+   reply = eldbus_message_method_return_new(iwd_agent->pending_msg);
+   if (reply)
+   {
+      eldbus_message_arguments_append(reply, "s", passphrase);
+      eldbus_connection_send(eldbus_service_connection_get(iwd_agent->iface),
+                             reply, NULL, NULL, -1);
+   }
+
+   /* Clear pending request */
+   eina_stringshare_del(iwd_agent->pending_network_path);
+   iwd_agent->pending_network_path = NULL;
+   iwd_agent->pending_msg = NULL;
+
+   INF("Passphrase sent to iwd");
 }
 
 /* Cancel pending request */
 void
 iwd_agent_cancel(void)
 {
+   Eldbus_Message *reply;
+
    if (!iwd_agent) return;
 
+   /* Send cancellation reply if there's a pending request */
+   if (iwd_agent->pending_msg)
+   {
+      reply = eldbus_message_error_new(iwd_agent->pending_msg,
+                                        "net.connman.iwd.Agent.Error.Canceled",
+                                        "User cancelled");
+      if (reply)
+      {
+         eldbus_connection_send(eldbus_service_connection_get(iwd_agent->iface),
+                                reply, NULL, NULL, -1);
+      }
+   }
+
    eina_stringshare_del(iwd_agent->pending_network_path);
    eina_stringshare_del(iwd_agent->pending_passphrase);
    iwd_agent->pending_network_path = NULL;
    iwd_agent->pending_passphrase = NULL;
+   iwd_agent->pending_msg = NULL;
 
    DBG("Agent request cancelled");
 }
@@ -197,6 +235,7 @@ _agent_request_passphrase(const Eldbus_Service_Interface *iface EINA_UNUSED,
                           const Eldbus_Message *msg)
 {
    const char *network_path;
+   IWD_Network *net;
 
    if (!eldbus_message_arguments_get(msg, "o", &network_path))
    {
@@ -206,13 +245,33 @@ _agent_request_passphrase(const Eldbus_Service_Interface *iface EINA_UNUSED,
 
    INF("Passphrase requested for network: %s", network_path);
 
-   /* Store network path for reference */
+   /* Store network path and message for later reply */
    eina_stringshare_replace(&iwd_agent->pending_network_path, network_path);
+   iwd_agent->pending_msg = msg;
 
-   /* TODO: Show passphrase dialog (Phase 4) */
-   /* For now, just return an error to indicate we're not ready */
+   /* Find the network */
+   net = iwd_network_find(network_path);
+   if (!net)
+   {
+      ERR("Network not found: %s", network_path);
+      iwd_agent->pending_msg = NULL;
+      return eldbus_message_error_new(msg, "net.connman.iwd.Agent.Error.Canceled", "Network not found");
+   }
 
-   return eldbus_message_error_new(msg, "net.connman.iwd.Agent.Error.Canceled", "UI not implemented yet");
+   /* Show passphrase dialog - this will eventually call iwd_agent_set_passphrase */
+   /* We need to get the instance - for now, use the first one */
+   if (iwd_mod && iwd_mod->instances)
+   {
+      Instance *inst = eina_list_data_get(iwd_mod->instances);
+      if (inst)
+      {
+         extern void wifi_auth_dialog_show(Instance *inst, IWD_Network *net);
+         wifi_auth_dialog_show(inst, net);
+      }
+   }
+
+   /* Return NULL to indicate we'll reply later (async) */
+   return NULL;
 }
 
 /* Cancel method */