feat(welcome): New project flow + per-repo account roadblock (T-488)

The UI half of the new-project flow (story T-486). A "New project…" welcome
action opens a dialog (location + name) that dispatches project.new (T-487),
opens the result, and announces it on projectCreatedChannel. The Claude
extension consumes that and shows the account roadblock — the embedded
per-workspace picker + accounts list, so a fresh project gets bound to an
account (or Default) right at birth.

The two halves stay decoupled: the welcome builtin only publishes the event
(no claude import); the claude builtin owns the account dialog. Only freshly-
created projects announce, so existing opens are never prompted.

Closes T-488. The non-repo "initialize as a project" path (T-489) is next.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/builtin/claude/src/account_roadblock_dialog.dart

@@ -0,0 +1,76 @@
+/// The per-repo account roadblock shown right after a new project is created
+/// (T-488, story T-486). Only a freshly-created project reaches here (the
+/// welcome dialog announces it on projectCreatedChannel) — existing opens never
+/// prompt. The new project is already the open workspace, so the embedded
+/// per-workspace picker binds it directly; the accounts list lets a first-run
+/// user add + sign in to an account before picking. No-Material (D-7).
+library;
+
+import 'package:clide/builtin/claude/src/account_settings_control.dart';
+import 'package:clide/widgets/widgets.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+
+class ClaudeAccountRoadblockDialog extends StatelessWidget {
+  const ClaudeAccountRoadblockDialog({super.key, required this.projectName, required this.onClose});
+
+  final String projectName;
+  final VoidCallback onClose;
+
+  KeyEventResult _onKey(FocusNode node, KeyEvent e) {
+    if (e is KeyDownEvent && e.logicalKey == LogicalKeyboardKey.escape) {
+      onClose();
+      return KeyEventResult.handled;
+    }
+    return KeyEventResult.ignored;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ClideSettings.theme.of(context).surface;
+    return Focus(
+      autofocus: true,
+      onKeyEvent: _onKey,
+      child: Container(
+        width: 560,
+        constraints: const BoxConstraints(maxHeight: 540),
+        decoration: BoxDecoration(
+          color: theme.modalSurfaceBackground,
+          border: Border.all(color: theme.modalSurfaceBorder),
+          borderRadius: BorderRadius.circular(8),
+        ),
+        child: SingleChildScrollView(
+          child: Padding(
+            padding: const EdgeInsets.all(18),
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              crossAxisAlignment: CrossAxisAlignment.stretch,
+              children: [
+                ClideText('Claude account for $projectName', fontSize: clideFontDialogTitle, fontWeight: FontWeight.w600, color: theme.globalForeground),
+                const SizedBox(height: 4),
+                ClideText(
+                  'Pick which Claude account this new project runs under, or keep the default system login. You can change it later in Settings or the pane badge.',
+                  muted: true,
+                  fontSize: clideFontMeta,
+                ),
+                const SizedBox(height: 18),
+                ClideText('Account for this project', fontSize: clideFontMeta, muted: true),
+                const SizedBox(height: 6),
+                const Align(alignment: Alignment.centerLeft, child: ClaudeWorkspaceAccountControl()),
+                const SizedBox(height: 18),
+                ClideText('Accounts', fontSize: clideFontMeta, muted: true),
+                const SizedBox(height: 6),
+                const ClaudeAccountsListControl(),
+                const SizedBox(height: 18),
+                Align(
+                  alignment: Alignment.centerRight,
+                  child: ClideButton(label: 'Continue', onPressed: onClose),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/builtin/claude/src/extension.dart

@@ -4,6 +4,7 @@ import 'dart:io';
 import 'package:clide/clide.dart';
 import 'package:clide/builtin/claude/src/account_registry.dart';
 import 'package:clide/builtin/claude/src/account_login_dialog.dart';
+import 'package:clide/builtin/claude/src/account_roadblock_dialog.dart';
 import 'package:clide/builtin/claude/src/account_settings_control.dart';
 import 'package:clide/builtin/claude/src/activity_cluster.dart' show foldLevelFromName, kActivityFoldLevelKey, nextFoldLevel;
 import 'package:clide/builtin/claude/src/claude_config.dart';
@@ -20,6 +21,7 @@ import 'package:clide/builtin/claude/src/session_storage.dart';
 import 'package:clide/builtin/claude/src/ticket_pick_up.dart';
 import 'package:clide/builtin/claude/src/transcript_reader.dart' show ImageMessage;
 import 'package:clide/src/daemon/claude_account_commands.dart' show accountActionChannel;
+import 'package:clide/src/daemon/project_commands.dart' show projectCreatedChannel;
 import 'package:clide/src/daemon/image_commands.dart' show imageShowChannel;
 import 'package:clide/builtin/claude/src/team_chat_sidebar.dart' show TeamChatPane;
 import 'package:clide/builtin/claude/src/team_panel_host.dart';
@@ -530,6 +532,19 @@ class ClaudeExtension extends ClideExtension {
     // writes the registry then publishes here; only the UI layer can respawn
     // the workspace's panes onto the newly-bound account or delete a config dir.
     _subs.add(ctx.messages.subscribe(channel: accountActionChannel).listen(_onAccountAction));
+
+    // A freshly-created project (T-488) announces itself once it's open; show the
+    // per-repo account roadblock so the user binds it now (existing opens, which
+    // never announce, are never prompted).
+    _subs.add(ctx.messages.subscribe(channel: projectCreatedChannel).listen(_onProjectCreated));
+  }
+
+  void _onProjectCreated(Message m) {
+    final dir = m.data['dir'] as String?;
+    final ctx = _ctx;
+    if (dir == null || ctx == null) return;
+    final name = dir.split('/').where((s) => s.isNotEmpty).lastOrNull ?? dir;
+    ctx.dialog.show<Object>((c, dismiss) => ClaudeAccountRoadblockDialog(projectName: name, onClose: dismiss));
   }
 
   /// Side-effects for the `claude account` verbs (T-480). The dispatcher does

lib/builtin/welcome/src/welcome_view.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 
 import 'package:clide/clide.dart' show clideName, clideTagline, clideVersion;
 import 'package:clide/kernel/kernel.dart';
+import 'package:clide/src/daemon/project_commands.dart' show projectCreatedChannel;
 import 'package:clide/widgets/widgets.dart';
 import 'package:flutter/services.dart' show MissingPluginException;
 import 'package:flutter/widgets.dart';
@@ -198,10 +199,20 @@ class _StartColumn extends StatelessWidget {
           tokens: tokens,
           onTap: () => _openFolder(context),
         ),
+        _ActionRow(
+          icon: PhosphorIcons.byName('folder-plus'),
+          label: ClideSettings.i18n.string(context, 'action.newProject', namespace: 'builtin.welcome', placeholder: 'New project…'),
+          tokens: tokens,
+          onTap: () => _newProject(context),
+        ),
       ],
     );
   }
 
+  void _newProject(BuildContext context) {
+    kernel.dialog.show<Object>((ctx, dismiss) => _NewProjectDialog(kernel: kernel, onClose: () => dismiss()));
+  }
+
   void _openFolder(BuildContext context) async {
     try {
       final picked = await kernel.window.pickDirectory();
@@ -683,3 +694,178 @@ class _NotARepoDialog extends StatelessWidget {
     );
   }
 }
+
+/// New-project dialog (T-488, story T-486): pick a location + name, create the
+/// project via `project.new`, open it, and announce it on [projectCreatedChannel]
+/// so the Claude extension can run the per-repo account roadblock. Stays
+/// claude-free — the account step is the consumer's job, not this dialog's.
+class _NewProjectDialog extends StatefulWidget {
+  const _NewProjectDialog({required this.kernel, required this.onClose});
+  final KernelServices kernel;
+  final VoidCallback onClose;
+
+  @override
+  State<_NewProjectDialog> createState() => _NewProjectDialogState();
+}
+
+class _NewProjectDialogState extends State<_NewProjectDialog> {
+  final TextEditingController _parent = TextEditingController();
+  final TextEditingController _name = TextEditingController();
+  final FocusNode _parentFocus = FocusNode(debugLabel: 'new-project-parent');
+  final FocusNode _nameFocus = FocusNode(debugLabel: 'new-project-name');
+  String? _error;
+  bool _loading = false;
+
+  @override
+  void dispose() {
+    _parent.dispose();
+    _name.dispose();
+    _parentFocus.dispose();
+    _nameFocus.dispose();
+    super.dispose();
+  }
+
+  Future<void> _browse() async {
+    try {
+      final picked = await widget.kernel.window.pickDirectory();
+      if (picked != null && mounted) setState(() => _parent.text = picked);
+    } on MissingPluginException {
+      // No native picker on this platform — the user types the path instead.
+    }
+  }
+
+  Future<void> _create() async {
+    final name = _name.text.trim();
+    final parent = _parent.text.trim();
+    if (name.isEmpty) return setState(() => _error = 'Enter a project name.');
+    if (parent.isEmpty) return setState(() => _error = 'Choose a location.');
+    setState(() {
+      _loading = true;
+      _error = null;
+    });
+    final r = await widget.kernel.ipc.request(
+      'project.new',
+      args: {
+        'positional': [name],
+        'flags': {'dir': parent},
+      },
+    );
+    if (!mounted) return;
+    if (!r.ok) {
+      return setState(() {
+        _loading = false;
+        _error = r.error?.message ?? 'Could not create the project.';
+      });
+    }
+    final path = r.data['path'] as String;
+    // Open the new workspace, then announce it — only a freshly-created project
+    // announces, so only it triggers the account roadblock (T-488).
+    final opened = await widget.kernel.project.open(path);
+    if (opened) widget.kernel.panels.activateTab(Slots.workspace, 'claude.primary');
+    widget.kernel.messages.publish('welcome', projectCreatedChannel, {'dir': path});
+    widget.onClose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = ClideSettings.theme.of(context).surface;
+    return Container(
+      width: 460,
+      padding: const EdgeInsets.all(20),
+      decoration: BoxDecoration(
+        color: tokens.modalSurfaceBackground,
+        border: Border.all(color: tokens.modalSurfaceBorder),
+        borderRadius: BorderRadius.circular(6),
+      ),
+      child: Column(
+        mainAxisSize: MainAxisSize.min,
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          ClideText(
+            ClideSettings.i18n.string(context, 'dialog.newProject.title', namespace: 'builtin.welcome', placeholder: 'New project'),
+            fontSize: clideFontDialogTitle,
+            fontWeight: FontWeight.w600,
+          ),
+          const SizedBox(height: 4),
+          ClideText(
+            ClideSettings.i18n.string(
+              context,
+              'dialog.newProject.body',
+              namespace: 'builtin.welcome',
+              placeholder: 'Creates a git repo + a CLAUDE.md, then opens it.',
+            ),
+            muted: true,
+            fontSize: clideFontMeta,
+          ),
+          const SizedBox(height: 16),
+          _field(
+            tokens,
+            'Location',
+            _parent,
+            _parentFocus,
+            trailing: ClideButton(label: 'Browse…', onPressed: _browse),
+          ),
+          const SizedBox(height: 10),
+          _field(tokens, 'Name', _name, _nameFocus, onSubmit: _create),
+          if (_error != null) ...[const SizedBox(height: 8), ClideText(_error!, color: tokens.statusError, fontSize: clideFontSmall)],
+          const SizedBox(height: 16),
+          Row(
+            mainAxisAlignment: MainAxisAlignment.end,
+            children: [
+              ClideButton(
+                label: ClideSettings.i18n.string(context, 'button.cancel', namespace: 'builtin.welcome', placeholder: 'Cancel'),
+                onPressed: widget.onClose,
+              ),
+              const SizedBox(width: 8),
+              ClideButton(
+                label: _loading
+                    ? ClideSettings.i18n.string(context, 'button.creating', namespace: 'builtin.welcome', placeholder: 'Creating…')
+                    : ClideSettings.i18n.string(context, 'button.create', namespace: 'builtin.welcome', placeholder: 'Create'),
+                onPressed: _loading ? null : _create,
+              ),
+            ],
+          ),
+        ],
+      ),
+    );
+  }
+
+  Widget _field(SurfaceTokens tokens, String label, TextEditingController c, FocusNode f, {Widget? trailing, Future<void> Function()? onSubmit}) {
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        ClideText(label, fontSize: clideFontMeta, muted: true),
+        const SizedBox(height: 4),
+        Row(
+          children: [
+            Expanded(
+              child: Container(
+                padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 6),
+                decoration: BoxDecoration(
+                  color: tokens.panelBackground,
+                  border: Border.all(color: f.hasFocus ? tokens.panelActiveBorder : tokens.globalBorder),
+                  borderRadius: BorderRadius.circular(4),
+                ),
+                child: EditableText(
+                  controller: c,
+                  focusNode: f,
+                  style: TextStyle(
+                    color: tokens.globalForeground,
+                    fontSize: clideFontCaption,
+                    fontFamily: ClideSettings.fonts.monoOf(context),
+                    fontFamilyFallback: clideMonoFamilyFallback,
+                  ),
+                  cursorColor: tokens.globalForeground,
+                  backgroundCursorColor: tokens.globalTextMuted,
+                  maxLines: 1,
+                  onSubmitted: onSubmit == null ? null : (_) => unawaited(onSubmit()),
+                ),
+              ),
+            ),
+            if (trailing != null) ...[const SizedBox(width: 8), trailing],
+          ],
+        ),
+      ],
+    );
+  }
+}

lib/src/daemon/project_commands.dart

@@ -15,6 +15,13 @@ import '../ipc/envelope.dart';
 import '../ipc/schema_v1.dart';
 import 'dispatcher.dart';
 
+/// MessageBus channel announcing a freshly-created project (path in `dir`). The
+/// welcome new-project dialog publishes it after create + open; the Claude
+/// extension consumes it to show the per-repo account roadblock (T-488) — only
+/// NEW projects prompt, existing opens never do. Lives here in the neutral
+/// daemon layer so both builtins name one literal without coupling to each other.
+const projectCreatedChannel = 'project.created';
+
 /// Runs `git init` in [dir]. Injected so this stays Flutter-free + testable;
 /// main.dart wires it to the real toolchain.
 typedef ProjectGitInit = Future<void> Function(String dir);