MVP: Go daemon, password auth, persistent PTY terminals, React/xterm UI, PWA

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/store/store.go

@@ -0,0 +1,71 @@
+// Package store persists small runtime state (terminal names, login sessions)
+// to a JSON file with atomic writes.
+package store
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"sync"
+	"time"
+)
+
+type Terminal struct {
+	ID   string `json:"id"`
+	Name string `json:"name"`
+}
+
+type State struct {
+	Terminals []Terminal           `json:"terminals"`
+	Sessions  map[string]time.Time `json:"sessions"` // token -> expiry
+}
+
+type Store struct {
+	mu    sync.Mutex
+	path  string
+	state State
+}
+
+func Open(path string) (*Store, error) {
+	s := &Store{path: path}
+	b, err := os.ReadFile(path)
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
+		return nil, err
+	}
+	if err == nil {
+		if err := json.Unmarshal(b, &s.state); err != nil {
+			return nil, err
+		}
+	}
+	if s.state.Sessions == nil {
+		s.state.Sessions = map[string]time.Time{}
+	}
+	return s, nil
+}
+
+// Update applies fn under the lock and writes the result to disk.
+func (s *Store) Update(fn func(*State)) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	fn(&s.state)
+	return s.save()
+}
+
+// View reads state under the lock.
+func (s *Store) View(fn func(*State)) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	fn(&s.state)
+}
+
+func (s *Store) save() error {
+	b, err := json.MarshalIndent(&s.state, "", "  ")
+	if err != nil {
+		return err
+	}
+	tmp := s.path + ".tmp"
+	if err := os.WriteFile(tmp, b, 0o600); err != nil {
+		return err
+	}
+	return os.Rename(tmp, s.path)
+}