feat(env): per-workspace PATH preset injected at spawn (T-511)

Implements D-106. The T-439 login-shell probe is a global heuristic
with a known hole — login-but-non-interactive shells skip ~/.bashrc,
so interactive-only additions (brew shellenv) never reach the agent's
Bash tool or terminal panes on a desktop launch. The preset is the
explicit per-repo layer on top: user-scope storage keyed by repo
identity (a linked worktree resolves through its gitdir pointer to the
main repo, so worktrees share the preset), prepended at spawn via the
PaneRegistry pathForSpawn hook and agentEnvDelta prependDirs — which
now exports PATH even when clide is already resolvable, closing the
gap where the hosted session inherited the sparse GUI PATH untouched.

CLI half: `clide env path list|set|add|remove|clear|capture` over an
injected Flutter-free store port; capture diffs the login-shell PATH
against the process PATH to suggest the dirs a desktop launch dropped.
Binary resolution (toolchain, supporter pins, bundled pql/git) stays
preset-blind per the D-92/T-98 fence.

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

lib/main.dart

@@ -40,6 +40,7 @@ import 'package:clide/builtin/claude/src/account_registry.dart';
 import 'package:clide/clide.dart' show clideVersion;
 import 'package:clide/src/daemon/claude_account_commands.dart';
 import 'package:clide/src/daemon/dispatcher.dart';
+import 'package:clide/src/daemon/env_path_commands.dart';
 import 'package:clide/src/daemon/draw_commands.dart';
 import 'package:clide/src/draw/compare_template.dart' show compareTemplateHandler;
 import 'package:clide/src/draw/d2_template.dart' show d2TemplateHandler;
@@ -62,7 +63,8 @@ import 'package:clide/src/daemon/search_commands.dart';
 import 'package:clide/src/editor/registry.dart' show EditorRegistry;
 import 'package:clide/src/git/client.dart';
 import 'package:clide/src/cli/argv_dispatch.dart';
-import 'package:clide/src/env/shell_env.dart' show primeLoginShellPath;
+import 'package:clide/src/env/path_preset.dart' show applyPathPreset, pathPresetKey, presetDirsFrom;
+import 'package:clide/src/env/shell_env.dart' show primeLoginShellPath, resolvedToolPath;
 import 'package:clide/src/env/supporter_binaries.dart';
 import 'package:clide/widgets/src/icons/phosphor_glyphs.g.dart' show kPhosphorGlyphs;
 import 'package:clide/src/ipc/envelope.dart';
@@ -310,7 +312,19 @@ Future<void> main() async {
             crumbPath: '${logDirectory()}/clide-pty.crumbs.log',
             verbose: log.minLevel.index <= LogLevel.debug.index,
           );
-    final paneRegistry = PaneRegistry(events: eventSink, ptyLog: ptyLog);
+    // Terminal PTY children get the workspace's PATH preset (D-106) prepended
+    // to the resolved login-shell PATH. Read live per spawn off the kernel
+    // settings (null pre-boot → plain resolved PATH, same as before).
+    final paneRegistry = PaneRegistry(
+      events: eventSink,
+      ptyLog: ptyLog,
+      pathForSpawn: (cwd) {
+        final settings = kernelSettings;
+        final base = resolvedToolPath();
+        if (settings == null) return base;
+        return applyPathPreset(base, presetDirsFrom((k) => settings.get<Object>(k), cwd ?? workRoot.path));
+      },
+    );
     // D-6 parity (T-219, D-83): make the tabs the user sees in the GUI
     // visible to `pane list` by snapshotting the kernel PanelRegistry +
     // LayoutArrangement at request time — no mirrored state to drift.
@@ -440,6 +454,18 @@ Future<void> main() async {
       publisher: () => kernelMessages?.publish,
       workspaceCwd: () => workRoot.path,
     );
+    // `clide env path …` — the per-workspace PATH preset's CLI half (D-106,
+    // T-511). Reads/writes the user-scope preset key through the kernel
+    // settings; mutations publish on envPathChannel.
+    registerEnvPathCommands(
+      dispatcher,
+      () {
+        final settings = kernelSettings;
+        return settings == null ? null : _PathPresetStoreAdapter(settings);
+      },
+      publisher: () => kernelMessages?.publish,
+      workspaceCwd: () => workRoot.path,
+    );
     // `clide status` — one-shot orientation snapshot (T-221): active pane,
     // focused file + selection, git summary, layout. Assembled here where the
     // live kernel + subsystem state is in scope; the reader's viewed doc is
@@ -655,6 +681,24 @@ class _AccountStoreAdapter implements AccountStore {
   Future<void> unbind(String cwd) => _reg.unbindWorkspace(cwd);
 }
 
+/// Adapts the (foundation-bound) [SettingsStore] to the Flutter-free
+/// [PathPresetStore] port the `env path` verbs use (D-106, T-511). The key is
+/// worktree-aware ([pathPresetKey]); an empty preset removes the key rather
+/// than leaving an empty list in settings.yaml.
+class _PathPresetStoreAdapter implements PathPresetStore {
+  _PathPresetStoreAdapter(this._settings);
+  final SettingsStore _settings;
+
+  @override
+  List<String> dirsFor(String cwd) => presetDirsFrom((k) => _settings.get<Object>(k), cwd);
+
+  @override
+  Future<void> setFor(String cwd, List<String> dirs) {
+    final key = pathPresetKey(cwd);
+    return dirs.isEmpty ? _settings.removeAt(SettingsScope.app, key) : _settings.setAt(SettingsScope.app, key, dirs);
+  }
+}
+
 class _BusEventSink implements DaemonEventSink {
   _BusEventSink(this._bus);
   final DaemonBus _bus;