feat(app): multiline composer with inline model & thinking selectors

app/lib/desktop/chat/desktop_chat_pane.dart

@@ -16,6 +16,7 @@ import '../../ui/session/tool_renderers.dart' show kReadableContentMaxWidth;
 import 'composer_focus.dart';
 import 'selected_session.dart';
 import 'sidebar_layout.dart';
+import '../../ui/composer/composer_selectors.dart';
 
 /// The right-hand pane of the desktop two-pane chat: transcript + docked
 /// composer for [selectedSessionProvider].
@@ -174,6 +175,11 @@ class _DesktopChatPaneState extends ConsumerState<DesktopChatPane> {
                 onSend: (text) => _handleSend(sessionId, text),
                 onCancel: () => _cancelTurn(sessionId),
                 running: running,
+                alwaysExpanded: true,
+                footerActions: [
+                  ComposerModelSelector(sessionId: sessionId),
+                  ComposerThinkingSelector(sessionId: sessionId),
+                ],
                 focusNode: ref.watch(desktopComposerFocusProvider),
                 sendChord: ref
                     .watch(keymapProvider)
@@ -282,9 +288,8 @@ class _PaneHeader extends ConsumerWidget {
     );
   }
 
-  /// Session-level overflow menu (Rename / Model / Thinking / Quit). Mirrors
-  /// the mobile [SessionScreen] top-bar menu so both platforms expose the same
-  /// actions.
+  /// Session-level overflow menu (Rename / Quit). Model and thinking-effort
+  /// live inline in the composer footer now, so they are not repeated here.
   Widget _actionsMenu(BuildContext context, WidgetRef ref) {
     return PopupMenuButton<String>(
       tooltip: 'Session actions',
@@ -305,20 +310,6 @@ class _PaneHeader extends ConsumerWidget {
               ref: ref,
               sessionId: fallbackId,
             );
-          case 'model':
-            handleClientCommand(
-              '/model',
-              context: context,
-              ref: ref,
-              sessionId: fallbackId,
-            );
-          case 'thinking':
-            handleClientCommand(
-              '/thinking',
-              context: context,
-              ref: ref,
-              sessionId: fallbackId,
-            );
           case 'quit':
             _confirmQuit(context, ref);
         }
@@ -332,22 +323,6 @@ class _PaneHeader extends ConsumerWidget {
             contentPadding: EdgeInsets.zero,
           ),
         ),
-        PopupMenuItem(
-          value: 'model',
-          child: ListTile(
-            leading: Icon(Symbols.smart_toy, weight: 200),
-            title: Text('Model'),
-            contentPadding: EdgeInsets.zero,
-          ),
-        ),
-        PopupMenuItem(
-          value: 'thinking',
-          child: ListTile(
-            leading: Icon(Symbols.psychology, weight: 200),
-            title: Text('Thinking'),
-            contentPadding: EdgeInsets.zero,
-          ),
-        ),
         PopupMenuDivider(),
         PopupMenuItem(
           value: 'quit',
@@ -785,7 +760,11 @@ class _WorktreeStartViewState extends ConsumerState<_WorktreeStartView> {
             ),
             child: Padding(
               padding: const EdgeInsets.fromLTRB(12, 4, 12, 12),
-              child: Composer(onSend: _start, running: _starting),
+              child: Composer(
+                onSend: _start,
+                running: _starting,
+                alwaysExpanded: true,
+              ),
             ),
           ),
         ),

app/lib/ui/composer/composer.dart

@@ -9,12 +9,14 @@ import 'slash_palette.dart';
 ///
 /// Two visual states:
 /// - **Compact** (unfocused): `[+] [1-line field] [send?]`.
-/// - **Expanded** (focused): full-width 3-line field on top, with
-///   `[+] … [send?]` in an action row beneath it.
+/// - **Expanded** (focused, or always on desktop): an auto-growing multiline
+///   field on top (grows with the caret up to 10 lines, then scrolls), with a
+///   footer row beneath it: `[footerActions…] … [+] [send?]`.
 ///
-/// Tapping into the field expands it; losing focus collapses it back to the
-/// 1-line compact form (text is preserved). The send button fades in only
-/// while the field is non-empty.
+/// On mobile the field is compact until focused, then expands to the full
+/// form; losing focus collapses it back to the 1-line compact form (text is
+/// preserved). On desktop [alwaysExpanded] keeps the full form up permanently.
+/// The send button fades in only while the field is non-empty.
 class Composer extends StatefulWidget {
   const Composer({
     super.key,
@@ -26,9 +28,21 @@ class Composer extends StatefulWidget {
     this.sendChord,
     this.newlineChord,
     this.focusNode,
+    this.footerActions = const <Widget>[],
+    this.alwaysExpanded = false,
   });
   final void Function(String text) onSend;
 
+  /// Leading controls placed on the left of the footer action row when the
+  /// composer is in its full (expanded) form — e.g. the model + thinking
+  /// selectors. Each may render nothing (a shrunk box) when it has no data.
+  final List<Widget> footerActions;
+
+  /// When true the composer is permanently in its full form (multiline field +
+  /// footer), regardless of focus. Desktop sets this; mobile leaves it false so
+  /// the field collapses to a one-liner when unfocused.
+  final bool alwaysExpanded;
+
   /// The chord that sends the message. Null uses the built-in default
   /// (⌘/Ctrl+Enter), which keeps mobile behavior unchanged.
   final KeyChord? sendChord;
@@ -113,6 +127,10 @@ class _ComposerState extends State<Composer> {
     setState(() => _showSlash = false);
   }
 
+  /// Whether to show the full (multiline + footer) form: always on desktop,
+  /// otherwise only while the field is focused.
+  bool get _expanded => widget.alwaysExpanded || _isFocused;
+
   @override
   Widget build(BuildContext context) {
     final cs = Theme.of(context).colorScheme;
@@ -139,7 +157,7 @@ class _ComposerState extends State<Composer> {
               duration: const Duration(milliseconds: 220),
               curve: Curves.easeOutCubic,
               alignment: Alignment.bottomCenter,
-              child: _isFocused ? _buildExpanded(cs) : _buildCompact(cs),
+              child: _expanded ? _buildExpanded(cs) : _buildCompact(cs),
             ),
           ),
         ],
@@ -159,7 +177,9 @@ class _ComposerState extends State<Composer> {
     );
   }
 
-  /// Expanded: full-width 3-line field, then `[+] … [send?]` beneath.
+  /// Expanded: auto-growing multiline field, then a footer row with the
+  /// caller's [Composer.footerActions] on the left (model/thinking selectors)
+  /// and `[+] [send?]` on the right.
   Widget _buildExpanded(ColorScheme cs) {
     return Column(
       mainAxisSize: MainAxisSize.min,
@@ -170,8 +190,24 @@ class _ComposerState extends State<Composer> {
           padding: const EdgeInsets.only(top: 4),
           child: Row(
             children: [
+              // The selectors share the row's free space and shrink (their
+              // labels ellipsize) rather than overflowing on narrow widths.
+              // Expanded here also stands in for the trailing Spacer, pushing
+              // [+]/send to the right when the actions are short or absent.
+              Expanded(
+                child: Row(
+                  children: [
+                    for (final action in widget.footerActions)
+                      Flexible(
+                        child: Padding(
+                          padding: const EdgeInsets.only(right: 6),
+                          child: action,
+                        ),
+                      ),
+                  ],
+                ),
+              ),
               _buildPlus(),
-              const Spacer(),
               // Reserve the send button's footprint so the layout doesn't
               // jump when the send button fades in/out.
               SizedBox(width: 48, child: _buildSendSlot()),
@@ -271,9 +307,10 @@ class _ComposerState extends State<Composer> {
           key: _fieldKey, // stable element across compact↔expanded reparenting
           controller: _ctrl,
           focusNode: _focus,
-          // Compact = exactly 1 line; expanded = fixed 3 lines (scrolls past).
-          minLines: _isFocused ? 3 : 1,
-          maxLines: _isFocused ? 3 : 1,
+          // Compact = exactly 1 line; expanded auto-grows with the caret up to
+          // 10 lines, then scrolls internally.
+          minLines: 1,
+          maxLines: _expanded ? 10 : 1,
           textCapitalization: TextCapitalization.sentences,
           // Return behavior is driven by _shortcuts(): unconfigured (mobile)
           // keeps the native Return-inserts-newline action, with sending via

app/lib/ui/composer/composer_selectors.dart

@@ -0,0 +1,120 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:material_symbols_icons/symbols.dart';
+
+import '../../store/store.dart';
+import '../home/repo_chips.dart' show AgentAvatar;
+import 'client_commands.dart';
+
+/// Small rounded pill used in the composer footer: a leading widget (agent
+/// avatar or icon) + a short label, tappable to open a picker. Kept visually
+/// low-key so it reads as an inline control, not a primary button.
+class _ComposerPill extends StatelessWidget {
+  const _ComposerPill({
+    required this.leading,
+    required this.label,
+    required this.onTap,
+    this.tooltip,
+  });
+
+  final Widget leading;
+  final String label;
+  final VoidCallback onTap;
+  final String? tooltip;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final cs = theme.colorScheme;
+    final pill = InkWell(
+      onTap: onTap,
+      borderRadius: BorderRadius.circular(14),
+      child: Padding(
+        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
+        child: Row(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            leading,
+            const SizedBox(width: 6),
+            Flexible(
+              child: Text(
+                label,
+                maxLines: 1,
+                overflow: TextOverflow.ellipsis,
+                style: theme.textTheme.labelMedium?.copyWith(
+                  color: cs.onSurfaceVariant,
+                ),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+    return tooltip == null ? pill : Tooltip(message: tooltip!, child: pill);
+  }
+}
+
+/// Composer-footer control that shows the session's current model and, on tap,
+/// opens the model picker (reusing the `/model` client command). Renders
+/// nothing until `session.meta` has arrived with a non-empty models list — the
+/// client fetches the selectable models asynchronously, so there is simply no
+/// selector to show in the meantime.
+class ComposerModelSelector extends ConsumerWidget {
+  /// Creates the model selector for [sessionId].
+  const ComposerModelSelector({super.key, required this.sessionId});
+
+  /// The session whose model this selector reads and switches.
+  final String sessionId;
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final meta = ref.watch(sessionMetaProvider(sessionId));
+    if (meta == null || meta.models.isEmpty) return const SizedBox.shrink();
+    final agent = ref.watch(sessionsProvider).byId(sessionId)?.agent ?? '';
+    return _ComposerPill(
+      leading: AgentAvatar(agent: agent, size: 16),
+      label: meta.model?.name ?? 'model',
+      tooltip: 'Model',
+      onTap: () => handleClientCommand(
+        '/model',
+        context: context,
+        ref: ref,
+        sessionId: sessionId,
+      ),
+    );
+  }
+}
+
+/// Composer-footer control that shows the session's current thinking
+/// (reasoning) effort and, on tap, opens the thinking-level picker (reusing the
+/// `/thinking` client command). Hidden entirely when the agent reports no
+/// thinking support (an empty thinking level).
+class ComposerThinkingSelector extends ConsumerWidget {
+  /// Creates the thinking-effort selector for [sessionId].
+  const ComposerThinkingSelector({super.key, required this.sessionId});
+
+  /// The session whose thinking level this selector reads and changes.
+  final String sessionId;
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final meta = ref.watch(sessionMetaProvider(sessionId));
+    if (meta == null || meta.thinking.isEmpty) return const SizedBox.shrink();
+    return _ComposerPill(
+      leading: Icon(
+        Symbols.signal_cellular_alt,
+        size: 16,
+        weight: 400,
+        color: Theme.of(context).colorScheme.onSurfaceVariant,
+      ),
+      label: meta.thinking,
+      tooltip: 'Thinking effort',
+      onTap: () => handleClientCommand(
+        '/thinking',
+        context: context,
+        ref: ref,
+        sessionId: sessionId,
+      ),
+    );
+  }
+}

app/lib/ui/session/session_screen.dart

@@ -9,6 +9,7 @@ import '../../store/models.dart';
 import '../../store/store.dart';
 import '../composer/client_commands.dart';
 import '../composer/composer.dart';
+import '../composer/composer_selectors.dart';
 import 'chat_message.dart';
 import 'tool_call_card.dart';
 import '../widgets/connection_chip.dart';
@@ -41,7 +42,6 @@ class _SessionScreenState extends ConsumerState<SessionScreen> {
   Widget build(BuildContext context) {
     final session = ref.watch(sessionsProvider).byId(widget.sessionId);
     final items = ref.watch(chatItemsProvider(widget.sessionId));
-    final meta = ref.watch(sessionMetaProvider(widget.sessionId));
 
     ref.listen<ActionError?>(sessionActionErrorProvider(widget.sessionId), (
       prev,
@@ -234,19 +234,6 @@ class _SessionScreenState extends ConsumerState<SessionScreen> {
                                     ],
                                   ),
                             ),
-                          if (meta?.model != null)
-                            Text(
-                              '${meta!.model!.name} · ${meta.thinking}',
-                              maxLines: 1,
-                              overflow: TextOverflow.ellipsis,
-                              style: Theme.of(context).textTheme.bodySmall
-                                  ?.copyWith(
-                                    color: cs.onSurface.withValues(alpha: 0.55),
-                                    shadows: [
-                                      Shadow(color: cs.surface, blurRadius: 6),
-                                    ],
-                                  ),
-                            ),
                         ],
                       ),
                     ),
@@ -278,6 +265,10 @@ class _SessionScreenState extends ConsumerState<SessionScreen> {
                     onSend: (text) => _handleSend(text),
                     running: session?.status == SessionStatus.running,
                     onCancel: _cancelTurn,
+                    footerActions: [
+                      ComposerModelSelector(sessionId: widget.sessionId),
+                      ComposerThinkingSelector(sessionId: widget.sessionId),
+                    ],
                   ),
                 ),
               ),