fix(#65): request POST_NOTIFICATIONS runtime permission on Android 13+ (#97)

* fix(#65): request POST_NOTIFICATIONS runtime permission on Android 13+

On API 33+ the manifest declaration alone is not enough — the app must
request POST_NOTIFICATIONS via ActivityResultContracts.RequestPermission
at runtime before it can show any notification, including the foreground
service notification from ChatNotificationService.

- Added rememberLauncherForActivityResult for POST_NOTIFICATIONS
- Added LaunchedEffect(Unit) that fires the permission request on first
  composition when running on API 33+ and permission is not yet granted
- The next lifecycle event (ON_STOP → NotificationHelper.start) picks
  up the permission if granted

* fix: add missing import android.os.Build for POST_NOTIFICATIONS permission check

* fix: add missing import for rememberLauncherForActivityResult (androidx.activity.compose)

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatScreen.kt

@@ -1,5 +1,8 @@
 package com.m57.hermescontrol.ui.chat
 
+import android.os.Build
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateContentSize
 import androidx.compose.animation.core.LinearEasing
@@ -85,6 +88,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.ImeAction
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.core.content.ContextCompat
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.m57.hermescontrol.notification.NotificationHelper
@@ -136,6 +140,26 @@ fun ChatScreen(
         }
     }
 
+    // Request POST_NOTIFICATIONS runtime permission on Android 13+ (API 33).
+    // The manifest declaration alone is insufficient — on API 33+ the system
+    // requires a runtime permission prompt before the app can post any
+    // notification, including the foreground service notification.
+    val requestNotificationPermission =
+        rememberLauncherForActivityResult(
+            contract = ActivityResultContracts.RequestPermission(),
+        ) { /* granted — next lifecycle event will pick it up */ }
+    LaunchedEffect(Unit) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            val permission = android.Manifest.permission.POST_NOTIFICATIONS
+            if (
+                ContextCompat.checkSelfPermission(context, permission) !=
+                android.content.pm.PackageManager.PERMISSION_GRANTED
+            ) {
+                requestNotificationPermission.launch(permission)
+            }
+        }
+    }
+
     // Auto-scroll to bottom on new messages
     LaunchedEffect(state.messages.size, state.currentStreamingText) {
         if (state.messages.isNotEmpty()) {