feat: i18n system, lang switch component, english subtitles, UI improvements, roadmap update

src/locales/en.json

@@ -0,0 +1,79 @@
+{
+  "ui": {
+    "start": "New Game",
+    "resume": "Continue",
+    "chapters": "Chapters",
+    "menu": "Menu",
+    "save": "Save",
+    "load": "Load",
+    "close": "Close",
+    "skip": "Skip",
+    "fullscreen": "Fullscreen",
+    "exitFullscreen": "Exit Fullscreen",
+    "gameEnd": "The End",
+    "choose": "Make your choice",
+    "back": "Back",
+    "autoSave": "Auto Save",
+    "empty": "Empty",
+    "loading": "Loading...",
+    "speed": "Speed",
+    "noAutoSave": "No auto save yet",
+    "autoSaveHint": "Game auto-saves to slot 0 at each scene change"
+  },
+  "scene": {
+    "intro": {
+      "choice": {
+        "left_door": "Walk toward the glowing door on the left",
+        "right_door": "Walk toward the ordinary door on the right",
+        "search": "Search the room carefully",
+        "stay": "Stay where you are, do nothing"
+      }
+    },
+    "left_door": {
+      "choice": {
+        "handshake": "Shake hands with the stranger",
+        "reject": "Refuse to shake, stay alert"
+      }
+    },
+    "right_door": {
+      "choice": {
+        "continue": "Keep moving forward",
+        "back": "Turn back"
+      }
+    },
+    "trust_ending": {
+      "choice": {
+        "journey": "Embark on a journey of trust (requires trust >= 80)",
+        "leave": "Leave this place"
+      }
+    },
+    "investigation_site": {
+      "choice": {
+        "leave": "Leave the room"
+      }
+    },
+    "desk_detail": {
+      "choice": {
+        "return": "Return to the crime scene",
+        "leave": "Leave"
+      }
+    },
+    "stay": {
+      "choice": {
+        "stand": "Stand up and leave"
+      }
+    },
+    "qte_success": {
+      "choice": {
+        "continue": "Keep moving forward",
+        "back": "Turn back"
+      }
+    },
+    "qte_fail": {
+      "choice": {
+        "continue": "Keep moving forward",
+        "back": "Turn back"
+      }
+    }
+  }
+}