feat: configurable bottom navigation bar (Issue #23)

## What
Adds a new Navigation Bar section to Settings where users can customize which items appear in the bottom navigation bar.

## Features
- Pick from any of the 19 drawer screens (max 5 items)
- Remove items with a close/delete button
- Items persist via SharedPreferences (CSV format)
- Invalid names are silently dropped
- Existing screens and auth-aware filtering respected

Closes #23

app/src/main/java/com/m57/hermescontrol/Navigation.kt

@@ -40,7 +40,9 @@ import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.material3.rememberDrawerState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.vector.ImageVector
@@ -73,7 +75,7 @@ import com.m57.hermescontrol.ui.system.SystemScreen as SystemScreenContent
 import com.m57.hermescontrol.ui.toolsets.ToolsetsScreen as ToolsetsScreenContent
 import com.m57.hermescontrol.ui.webhooks.WebhooksScreen as WebhooksScreenContent
 
-// ── Bottom-nav primary screens ─────────────────────────────────────────
+// ── Bottom-nav item model ──────────────────────────────────────────────
 
 private data class BottomNavItem(
     val key: NavKey,
@@ -81,16 +83,37 @@ private data class BottomNavItem(
     val icon: ImageVector,
 )
 
-private val BOTTOM_NAV_ITEMS =
+/** Master list of ALL screens available for bottom-nav selection. */
+private val ALL_NAV_ITEMS: List<BottomNavItem> =
     listOf(
         BottomNavItem(ChatScreen, "Chat", Icons.AutoMirrored.Filled.Chat),
         BottomNavItem(SkillsScreen, "Skills", Icons.Filled.Extension),
         BottomNavItem(CronJobsScreen, "Cron", Icons.Filled.Schedule),
         BottomNavItem(SystemScreen, "System", Icons.Filled.Info),
         BottomNavItem(SettingsScreen, "Settings", Icons.Filled.Settings),
+        BottomNavItem(ProfilesScreen, "Profiles", Icons.Filled.AccountCircle),
+        BottomNavItem(WebhooksScreen, "Webhooks", Icons.Filled.Webhook),
+        BottomNavItem(GatewayScreen, "Gateway", Icons.Filled.Bolt),
+        BottomNavItem(ToolsetsScreen, "Toolsets", Icons.Filled.Build),
+        BottomNavItem(PluginsScreen, "Plugins", Icons.Filled.Memory),
+        BottomNavItem(ConfigScreen, "Config", Icons.Filled.Code),
+        BottomNavItem(McpServersScreen, "MCP Servers", Icons.Filled.Dashboard),
+        BottomNavItem(ModelScreen, "Models", Icons.Filled.Settings),
+        BottomNavItem(PairingScreen, "Pairing", Icons.Filled.Devices),
+        BottomNavItem(KeysScreen, "Keys", Icons.Filled.Key),
+        BottomNavItem(ChannelsScreen, "Channels", Icons.Filled.ListAlt),
+        BottomNavItem(LogsScreen, "Logs", Icons.Filled.HistoryEdu),
+        BottomNavItem(KanbanScreen, "Kanban", Icons.Filled.Dashboard),
+        BottomNavItem(AchievementsScreen, "Achievements", Icons.Filled.Info),
     )
 
-private val BOTTOM_NAV_KEYS: Set<NavKey> = BOTTOM_NAV_ITEMS.map { it.key }.toSet()
+/** Lookup: data-object simple name → NavKey (used by bottom-nav config). */
+private val NAV_KEY_BY_NAME: Map<String, NavKey> =
+    ALL_NAV_ITEMS.associate { it.key::class.simpleName!! to it.key }
+
+/** Resolve a persisted list of nav-item names to BottomNavItem instances. */
+private fun resolveBottomNavItems(names: List<String>): List<BottomNavItem> =
+    names.mapNotNull { name -> NAV_KEY_BY_NAME[name]?.let { key -> ALL_NAV_ITEMS.first { it.key == key } } }
 
 // ── Drawer sections for secondary screens ──────────────────────────────
 
@@ -130,7 +153,7 @@ private val DRAWER_ENTRIES =
         DrawerEntry(AchievementsScreen, "Achievements", Icons.Filled.Info, DrawerSection.INSPECT),
     )
 
-private val DRAWER_GESTURE_SCREENS: Set<NavKey> = BOTTOM_NAV_KEYS + DRAWER_ENTRIES.map { it.key }.toSet()
+private val DRAWER_GESTURE_SCREENS: Set<NavKey> = ALL_NAV_ITEMS.map { it.key }.toSet()
 
 @Composable
 fun MainNavigation() {
@@ -144,7 +167,16 @@ fun MainNavigation() {
     val drawerState = rememberDrawerState(initialValue = DrawerValue.Closed)
     val scope = rememberCoroutineScope()
 
-    val isPrimaryScreen = currentScreen in BOTTOM_NAV_KEYS
+    // Read dynamic bottom-nav config
+    val bottomNavItems = remember { resolveBottomNavItems(AuthManager.getBottomNavItems()) }
+    val bottomNavKeys = remember(bottomNavItems) { bottomNavItems.map { it.key }.toSet() }
+
+    // Sync primary screens to NavigationController
+    LaunchedEffect(bottomNavKeys) {
+        NavigationController.updatePrimaryScreens(bottomNavKeys)
+    }
+
+    val isPrimaryScreen = currentScreen in bottomNavKeys
     val gesturesEnabled = currentScreen in DRAWER_GESTURE_SCREENS
     val openDrawer = { scope.launch { drawerState.open() } }
 
@@ -222,7 +254,7 @@ fun MainNavigation() {
             bottomBar = {
                 if (isPrimaryScreen) {
                     NavigationBar {
-                        BOTTOM_NAV_ITEMS.forEach { item ->
+                        bottomNavItems.forEach { item ->
                             NavigationBarItem(
                                 selected = currentScreen == item.key,
                                 onClick = { NavigationController.navigateTo(item.key) },

app/src/main/java/com/m57/hermescontrol/NavigationController.kt

@@ -17,9 +17,11 @@ import androidx.navigation3.runtime.NavKey
 object NavigationController {
     var backStack: NavBackStack<NavKey>? = null
 
-    // Bottom-nav primary screens — tapping one clears the stack to root.
-    private val primaryScreens: Set<NavKey> =
-        setOf(
+    // Bottom-nav primary screens — dynamic, updated by Navigation.kt via
+    // updatePrimaryScreens() when the user customises the bottom nav bar.
+    // Default matches the default 5 bottom-nav items.
+    private val primaryScreens: MutableSet<NavKey> =
+        mutableSetOf(
             ChatScreen,
             SkillsScreen,
             CronJobsScreen,
@@ -27,11 +29,21 @@ object NavigationController {
             SettingsScreen,
         )
 
+    /** Returns whether the given key is a primary (bottom-nav) screen. */
+    fun isPrimaryScreen(key: NavKey): Boolean = key in primaryScreens
+
+    /** Replace the primary screen set. Called by Navigation.kt when the
+     *  bottom-nav item config changes. */
+    fun updatePrimaryScreens(keys: Set<NavKey>) {
+        primaryScreens.clear()
+        primaryScreens.addAll(keys)
+    }
+
     fun navigateTo(key: NavKey) {
         val stack = backStack ?: return
         if (stack.lastOrNull() == key) return
 
-        if (key in primaryScreens) {
+        if (isPrimaryScreen(key)) {
             stack.clear()
         }
         stack.add(key)

app/src/main/java/com/m57/hermescontrol/data/local/AuthManager.kt

@@ -20,6 +20,7 @@ object AuthManager {
     private const val KEY_PORT = "port"
     private const val KEY_AUTO_RECONNECT = "auto_reconnect"
     private const val KEY_THEME_PREFERENCE = "theme_preference"
+    private const val KEY_BOTTOM_NAV_ITEMS = "bottom_nav_items"
 
     private const val DEFAULT_HOST = "127.0.0.1"
     private const val DEFAULT_PORT = 9119
@@ -117,4 +118,21 @@ object AuthManager {
     /** Convenience: build the WebSocket URL with token query param.
      *  NOTE: Token in query string — trusted local network only. */
     fun wsUrl(): String = "ws://${getHost()}:${getPort()}/api/ws?token=${getToken().orEmpty()}"
+
+    // ── Bottom nav bar items ──────────────────────────────────────────────
+
+    /** Default bottom-nav items (NavKey data-object names). */
+    private val DEFAULT_BOTTOM_NAV_ITEMS =
+        listOf("ChatScreen", "SkillsScreen", "CronJobsScreen", "SystemScreen", "SettingsScreen")
+
+    /** Returns the list of selected bottom-nav item keys (data-object names). */
+    fun getBottomNavItems(): List<String> {
+        val raw = requirePrefs().getString(KEY_BOTTOM_NAV_ITEMS, null) ?: return DEFAULT_BOTTOM_NAV_ITEMS
+        return raw.split(",").filter { it.isNotBlank() }
+    }
+
+    /** Persist the ordered list of bottom-nav item keys (max 5, data-object names). */
+    fun setBottomNavItems(items: List<String>) {
+        requirePrefs().edit().putString(KEY_BOTTOM_NAV_ITEMS, items.joinToString(",")).apply()
+    }
 }

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsScreen.kt

@@ -5,6 +5,7 @@ import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -17,6 +18,8 @@ import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Visibility
 import androidx.compose.material.icons.filled.VisibilityOff
 import androidx.compose.material3.Button
@@ -24,6 +27,8 @@ import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -227,6 +232,60 @@ fun SettingsScreen(
                 }
             }
 
+            // Navigation Bar section
+            SectionCard(title = "Navigation Bar") {
+                Text(
+                    text = "Bottom bar items (${state.selectedNavItems.size}/5)",
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+                Spacer(modifier = Modifier.height(8.dp))
+
+                state.selectedNavItems.forEach { name ->
+                    val label = viewModel.availableNavItems.firstOrNull { it.first == name }?.second ?: name
+                    Row(
+                        modifier = Modifier.fillMaxWidth().padding(vertical = 2.dp),
+                        horizontalArrangement = Arrangement.SpaceBetween,
+                        verticalAlignment = Alignment.CenterVertically,
+                    ) {
+                        Text(text = label, style = MaterialTheme.typography.bodyMedium)
+                        IconButton(onClick = { viewModel.removeNavItem(name) }) {
+                            Icon(Icons.Filled.Close, contentDescription = "Remove $label")
+                        }
+                    }
+                }
+
+                if (state.selectedNavItems.size < 5) {
+                    val available = viewModel.availableNavItems.filter { it.first !in state.selectedNavItems }
+                    if (available.isNotEmpty()) {
+                        var expanded by remember { mutableStateOf(false) }
+                        Box {
+                            OutlinedButton(onClick = { expanded = true }) {
+                                Icon(Icons.Filled.Add, contentDescription = null)
+                                Spacer(Modifier.size(4.dp))
+                                Text("Add Item")
+                            }
+                            DropdownMenu(expanded = expanded, onDismissRequest = { expanded = false }) {
+                                available.forEach { (name, label) ->
+                                    DropdownMenuItem(
+                                        text = { Text(label) },
+                                        onClick = {
+                                            viewModel.addNavItem(name)
+                                            expanded = false
+                                        },
+                                    )
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    Text(
+                        text = "Maximum of 5 items",
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+
             // Test result
             AnimatedVisibility(
                 visible = state.testResult != null,

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsViewModel.kt

@@ -22,6 +22,7 @@ data class SettingsUiState(
     val isTesting: Boolean = false,
     val testResult: String? = null,
     val isSaved: Boolean = false,
+    val selectedNavItems: List<String> = emptyList(),
 )
 
 class SettingsViewModel : ViewModel() {
@@ -43,6 +44,7 @@ class SettingsViewModel : ViewModel() {
                 // choice from persistent storage on init. Previously this slot
                 // was missing — always defaulted to ThemePreference.SYSTEM.
                 themePreference = AuthManager.getThemePreference(),
+                selectedNavItems = AuthManager.getBottomNavItems(),
             )
         }
     }
@@ -67,6 +69,52 @@ class SettingsViewModel : ViewModel() {
         _uiState.update { it.copy(themePreference = theme, isSaved = false) }
     }
 
+    /** All screens available for bottom-nav selection (name → display label). */
+    val availableNavItems: List<Pair<String, String>> =
+        listOf(
+            "ChatScreen" to "Chat",
+            "SkillsScreen" to "Skills",
+            "CronJobsScreen" to "Cron Jobs",
+            "SystemScreen" to "System",
+            "SettingsScreen" to "Settings",
+            "ProfilesScreen" to "Profiles",
+            "WebhooksScreen" to "Webhooks",
+            "GatewayScreen" to "Gateway",
+            "ToolsetsScreen" to "Toolsets",
+            "PluginsScreen" to "Plugins",
+            "ConfigScreen" to "Config",
+            "McpServersScreen" to "MCP Servers",
+            "ModelScreen" to "Models",
+            "PairingScreen" to "Pairing",
+            "KeysScreen" to "Keys",
+            "ChannelsScreen" to "Channels",
+            "LogsScreen" to "Logs",
+            "KanbanScreen" to "Kanban",
+            "AchievementsScreen" to "Achievements",
+        )
+
+    /** Add a nav item to the bottom bar (max 5). Auto-saves. */
+    fun addNavItem(name: String) {
+        val current = _uiState.value.selectedNavItems
+        if (name in current || current.size >= 5) return
+        val updated = current + name
+        _uiState.update { it.copy(selectedNavItems = updated) }
+        AuthManager.setBottomNavItems(updated)
+    }
+
+    /** Remove a nav item from the bottom bar. Auto-saves. */
+    fun removeNavItem(name: String) {
+        val updated = _uiState.value.selectedNavItems - name
+        _uiState.update { it.copy(selectedNavItems = updated) }
+        AuthManager.setBottomNavItems(updated)
+    }
+
+    /** Reorder the selected nav items. Auto-saves. */
+    fun reorderNavItems(items: List<String>) {
+        _uiState.update { it.copy(selectedNavItems = items) }
+        AuthManager.setBottomNavItems(items)
+    }
+
     fun save() {
         val state = _uiState.value
         val port = state.port.toIntOrNull() ?: 9119