add WorkspaceRef + remote identity on RecentProject (T-332)

The model-independent half of the ssh:// open scheme. WorkspaceRef is
the value type for "where a workspace lives" — a local path or
ssh://[user@]host[:port]/abs/path, with parse/uri round-tripping and a
host:path display form. RecentProject carries host/port/user
(back-compatible JSON: absent keys deserialize as local) so remote
recents survive restarts and render with their host badge.

The remaining T-332 scope — ProjectManager.current off bare Directory,
open() branching, remote resolveProject — is gated on the execution
layer (T-336), which is itself blocked on the T-330 footprint pick;
the epic's blocker graph now encodes that gating.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/kernel/src/project.dart

@@ -6,10 +6,20 @@ import 'package:clide/kernel/src/events/types.dart';
 import 'package:clide/kernel/src/log.dart';
 import 'package:clide/kernel/src/settings.dart';
 import 'package:clide/kernel/src/toolchain.dart';
+import 'package:clide/kernel/src/workspace_ref.dart';
 import 'package:flutter/foundation.dart';
 
 class RecentProject {
-  const RecentProject({required this.path, required this.name, this.branch, required this.lastOpened, this.startupSticky = false});
+  const RecentProject({
+    required this.path,
+    required this.name,
+    this.branch,
+    required this.lastOpened,
+    this.startupSticky = false,
+    this.host,
+    this.port,
+    this.user,
+  });
 
   final String path;
   final String name;
@@ -21,12 +31,27 @@ class RecentProject {
   /// opens it directly; otherwise the welcome screen takes over (T-115).
   final bool startupSticky;
 
+  /// Remote workspace identity (T-332/T-329): the SSH host (or
+  /// `~/.ssh/config` alias) the repo lives on. Absent = local — older
+  /// persisted recents deserialize as local automatically.
+  final String? host;
+  final int? port;
+  final String? user;
+
+  bool get isRemote => host != null;
+
+  /// This recent's location as a [WorkspaceRef].
+  WorkspaceRef get ref => host == null ? WorkspaceRef.local(path) : WorkspaceRef.remote(host: host!, path: path, port: port, user: user);
+
   RecentProject copyWith({bool? startupSticky, DateTime? lastOpened, String? branch}) => RecentProject(
     path: path,
     name: name,
     branch: branch ?? this.branch,
     lastOpened: lastOpened ?? this.lastOpened,
     startupSticky: startupSticky ?? this.startupSticky,
+    host: host,
+    port: port,
+    user: user,
   );
 
   Map<String, dynamic> toJson() => {
@@ -35,6 +60,9 @@ class RecentProject {
     'branch': branch,
     'lastOpened': lastOpened.toIso8601String(),
     if (startupSticky) 'startupSticky': true,
+    if (host != null) 'host': host,
+    if (port != null) 'port': port,
+    if (user != null) 'user': user,
   };
 
   factory RecentProject.fromJson(Map<String, dynamic> json) => RecentProject(
@@ -43,9 +71,13 @@ class RecentProject {
     branch: json['branch'] as String?,
     lastOpened: DateTime.tryParse(json['lastOpened'] as String? ?? '') ?? DateTime.now(),
     startupSticky: json['startupSticky'] as bool? ?? false,
+    host: json['host'] as String?,
+    port: json['port'] as int?,
+    user: json['user'] as String?,
   );
 
   String get relativePath {
+    if (isRemote) return '$host:$path';
     final home = Platform.environment['HOME'] ?? '';
     if (home.isNotEmpty && path.startsWith(home)) return '~${path.substring(home.length)}';
     return path;

lib/kernel/src/workspace_ref.dart

@@ -0,0 +1,64 @@
+/// WorkspaceRef (T-332): where a workspace lives — a local repo root or
+/// a repo on a remote host reached over SSH (T-329).
+///
+/// The remote form is written `ssh://[user@]host[:port]/abs/remote/path`
+/// (host may be a `~/.ssh/config` alias — resolution happens at connect
+/// time, not here). A bare string with no scheme is a local path.
+library;
+
+/// A reference to a workspace root. Immutable value type.
+class WorkspaceRef {
+  const WorkspaceRef.local(this.path) : host = null, port = null, user = null;
+
+  const WorkspaceRef.remote({required String this.host, required this.path, this.port, this.user});
+
+  /// Remote host (or `~/.ssh/config` alias). Null means local.
+  final String? host;
+
+  /// SSH port; null means the ssh default / config-resolved port.
+  final int? port;
+
+  /// SSH user; null means the local username / config-resolved user.
+  final String? user;
+
+  /// Absolute workspace path — on [host] when remote, locally otherwise.
+  final String path;
+
+  bool get isRemote => host != null;
+
+  /// Parse either a plain local path or an `ssh://` URI. Returns null
+  /// for a malformed `ssh://` form (no host, or no absolute path).
+  static WorkspaceRef? parse(String input) {
+    if (!input.startsWith('ssh://')) return WorkspaceRef.local(input);
+    final Uri uri;
+    try {
+      uri = Uri.parse(input);
+    } on FormatException {
+      return null;
+    }
+    if (uri.host.isEmpty || uri.path.isEmpty || uri.path == '/') return null;
+    return WorkspaceRef.remote(host: uri.host, path: uri.path, port: uri.hasPort ? uri.port : null, user: uri.userInfo.isEmpty ? null : uri.userInfo);
+  }
+
+  /// The canonical string form: the bare path locally, the full
+  /// `ssh://` URI remotely. `parse(uri) == ref` round-trips.
+  String get uri {
+    if (!isRemote) return path;
+    final auth = user == null ? host! : '$user@$host';
+    final p = port == null ? '' : ':$port';
+    return 'ssh://$auth$p$path';
+  }
+
+  /// Compact human form for recents/switcher rows: `host:path` remotely
+  /// (e.g. `buildbox:/srv/repo`), the bare path locally.
+  String get display => isRemote ? '$host:$path' : path;
+
+  @override
+  bool operator ==(Object other) => other is WorkspaceRef && other.host == host && other.port == port && other.user == user && other.path == path;
+
+  @override
+  int get hashCode => Object.hash(host, port, user, path);
+
+  @override
+  String toString() => 'WorkspaceRef($uri)';
+}