feat(rules): add game-specific metadata attachment and unify match metadata initialization

Added AttachGameMetadata to GameRules interface

Implemented metadata setup for Battleship (phase + readiness flags)

Implemented no-op metadata hook for TicTacToe

Moved generic phase/ready metadata out of MatchInit

Added game/mode metadata to match state

Fixed json:"metadata" tag in MatchState

plugins/games/battleship.go

@@ -89,7 +89,16 @@ func (b *BattleshipRules) InitBoards(players []*structs.Player, cfg GameConfigur
 // Assign player boards
 // ------------------------------
 func (b *BattleshipRules) AssignPlayerSymbols(players []*structs.Player) {
-    // nothing needed for classic mode
+    // nothing needed for battleship
+}
+
+// ------------------------------
+// Attach Game Metadata
+// ------------------------------
+func (b *BattleshipRules) AttachGameMetadata(state *structs.MatchState) {
+  state.Metadata["phase"] = "placement"
+  state.Metadata["p0_ready"] = false
+  state.Metadata["p1_ready"] = false
 }
 
 // ------------------------------

plugins/games/rules.go

@@ -21,6 +21,8 @@ type GameRules interface {
     // Assign symbols/colors/pieces at start.
     AssignPlayerSymbols(players []*structs.Player)
 
+    // Attach Game Metadata
+    AttachGameMetadata(state *structs.MatchState)
     // Apply a move.
     // Returns: (changed, gameOver, winnerIndex)
     ApplyMove(

plugins/games/tictactoe.go

@@ -31,6 +31,13 @@ func (t *TicTacToeRules) AssignPlayerSymbols(players []*structs.Player) {
     players[1].Metadata["symbol"] = "O"
 }
 
+// ------------------------------
+// Attach Game Metadata
+// ------------------------------
+func (b *TicTacToeRules) AttachGameMetadata(state *structs.MatchState) {
+    // nothing needed for tictactoe
+}
+
 // ValidateMove checks bounds and empty cell.
 func (t *TicTacToeRules) ValidateMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {
 

plugins/modules/match.go

@@ -130,9 +130,9 @@ func (m *GenericMatch) MatchInit(
 		GameOver: false,
 		Metadata: map[string]interface{}{},
 	}
-  state.Metadata["phase"] = "placement"
+  state.Metadata["game"] = m.GameName
-  state.Metadata["p0_ready"] = false
+  state.Metadata["mode"] = m.Mode
-  state.Metadata["p1_ready"] = false
+	m.Rules.AttachGameMetadata(state)
 
 	label := fmt.Sprintf("%s:%s", m.GameName, m.Mode)
 

plugins/structs/match_state.go

@@ -7,5 +7,5 @@ type MatchState struct {
   Turn     int                    `json:"turn"`        // index in Players[]
   Winner   int                    `json:"winner"`      // -1 = none, >=0 = winner index
   GameOver bool                   `json:"game_over"`   // true when the match ends
-  Metadata map[string]interface{} `json:metadata`     // metadata
+  Metadata map[string]interface{} `json:"metadata"`      // metadata
 }