feat(gui): gpt-5.4-mini/mature pass 4

- `dev` now points at `db535805a179ef11a012ff34994036ede2cb150d`

Co-Authored-By: Virgil <virgil@lethean.io>

.core/TODO.md

@@ -1 +1 @@
-- @bug pkg/window/state.go:26 — window state persistence writes to the default home config path, which breaks restricted test/runtime environments unless the target path is configurable.
+- @bug pkg/window/layout.go:29 — layout persistence has the same hard-coded config-dir assumption and needs an explicit file-path override for restricted runtimes.

pkg/window/state.go

@@ -10,6 +10,8 @@ import (
 	coreio "dappco.re/go/core/io"
 )
 
+const windowStateFileEnv = "WINDOW_STATE_FILE"
+
 // WindowState holds the persisted position/size of a window.
 // JSON tags match existing window_state.json format for backward compat.
 type WindowState struct {
@@ -23,7 +25,7 @@ type WindowState struct {
 	UpdatedAt int64  `json:"updatedAt,omitempty"`
 }
 
-// StateManager persists window positions to ~/.config/Core/window_state.json.
+// StateManager persists window positions to the configured window state file.
 type StateManager struct {
 	configDir string
 	statePath string
@@ -32,8 +34,12 @@ type StateManager struct {
 	saveTimer *time.Timer
 }
 
-// NewStateManager creates a StateManager loading from the default config directory.
+// NewStateManager creates a StateManager loading from the configured default path.
+// WINDOW_STATE_FILE overrides the directory-based default when present.
 func NewStateManager() *StateManager {
+	if stateFile := core.Env(windowStateFileEnv); stateFile != "" {
+		return NewStateManagerWithPath(stateFile)
+	}
 	sm := &StateManager{
 		states: make(map[string]WindowState),
 	}
@@ -55,6 +61,17 @@ func NewStateManagerWithDir(configDir string) *StateManager {
 	return sm
 }
 
+// NewStateManagerWithPath creates a StateManager loading from a custom state file.
+// Useful for tests or restricted runtimes that need an explicit writable target.
+func NewStateManagerWithPath(path string) *StateManager {
+	sm := &StateManager{
+		statePath: path,
+		states:    make(map[string]WindowState),
+	}
+	sm.load()
+	return sm
+}
+
 func (sm *StateManager) filePath() string {
 	if sm.statePath != "" {
 		return sm.statePath

pkg/window/state_test.go

@@ -20,6 +20,17 @@ func TestStateManagerState_NewStateManagerWithDir_Good(t *testing.T) {
 	assert.Empty(t, sm.ListStates())
 }
 
+func TestStateManagerState_NewStateManagerWithPathEnv_Good(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "custom", "window_state.json")
+	t.Setenv(windowStateFileEnv, path)
+
+	sm := NewStateManager()
+
+	require.NotNil(t, sm)
+	assert.Equal(t, path, sm.filePath())
+	assert.Equal(t, filepath.Dir(path), sm.dataDir())
+}
+
 func TestStateManagerState_NewStateManagerWithDir_Bad(t *testing.T) {
 	sm := NewStateManagerWithDir("")