feat: single-owner game state, transactional lifecycle, durable money on server stop

2 files changed, 26 insertions, 11 deletions

diff --git a/internal/player/player.go b/internal/player/player.go
index 81ef056..ae147b2 100644
--- a/internal/player/player.go
+++ b/internal/player/player.go
@@ -159,6 +159,11 @@ func GetOptionDef(name string) *OptionDef {
 
 type Player struct {
 	Name                   string                    `yaml:"name"`
+	// ID is a stable identifier assigned at creation. Filenames are
+	// renameable; the ID is not, so cached references authorize by ID.
+	ID                     string                    `yaml:"id,omitempty"`
+	// Account is the owning account name (case-canonical at write time).
+	Account                string                    `yaml:"account,omitempty"`
 	Skills                 map[SkillName]int         `yaml:"skills"`
 	Inventory              map[int]*InventorySlot    `yaml:"inventory"`
 	Bank                   map[int]*InventorySlot    `yaml:"bank"`
diff --git a/internal/player/store.go b/internal/player/store.go
index d0dbd0f..d461485 100644
--- a/internal/player/store.go
+++ b/internal/player/store.go
@@ -37,12 +37,17 @@ func (s *AccountStore) LoadAccount(name string) (*Account, error) {
 }
 
 func (s *AccountStore) SaveAccount(acc *Account) error {
-	path := s.AccountPath(acc.Name)
-	data, err := yaml.Marshal(acc)
+	data, err := s.MarshalAccount(acc)
 	if err != nil {
 		return err
 	}
-	return persistence.WriteFile(path, data, 0600)
+	return persistence.WriteFile(s.AccountPath(acc.Name), data, 0600)
+}
+
+// MarshalAccount serializes an account; callers that own the account (the
+// game owner, or transaction code holding it) may use this directly.
+func (s *AccountStore) MarshalAccount(acc *Account) ([]byte, error) {
+	return yaml.Marshal(acc)
 }
 
 func (s *AccountStore) AccountExists(name string) bool {
@@ -103,9 +108,18 @@ func (s *AccountStore) LoadCharacter(name string) (*Player, error) {
 }
 
 func (s *AccountStore) SaveCharacter(p *Player) error {
-	path := s.CharPath(p.Name)
-	// Serialize a value copy so saving god-mode stats never temporarily
-	// changes the live player. The caller still owns all referenced maps.
+	data, err := s.MarshalCharacter(p)
+	if err != nil {
+		return err
+	}
+	return persistence.WriteFile(s.CharPath(p.Name), data, 0600)
+}
+
+// MarshalCharacter serializes a character for a same-directory temporary
+// atomic write. It serializes a value snapshot so saving god-mode stats
+// never temporarily changes the live player; the caller still owns all
+// referenced maps (serialize on the owner goroutine).
+func (s *AccountStore) MarshalCharacter(p *Player) ([]byte, error) {
 	snapshot := *p
 	if snapshot.GodMode && snapshot.GodBackup != nil {
 		snapshot.Skills = snapshot.GodBackup
@@ -113,11 +127,7 @@ func (s *AccountStore) SaveCharacter(p *Player) error {
 			snapshot.HP = snapshot.MaxHP()
 		}
 	}
-	data, err := yaml.Marshal(&snapshot)
-	if err != nil {
-		return err
-	}
-	return persistence.WriteFile(path, data, 0600)
+	return yaml.Marshal(&snapshot)
 }
 
 func (s *AccountStore) CharacterExists(name string) bool {