feat: WorldInterface + Heartbeat v2 (#871, #872) (#900)

Co-authored-by: Perplexity Computer <perplexity@tower.local>
Co-committed-by: Perplexity Computer <perplexity@tower.local>

src/infrastructure/world/interface.py

@@ -0,0 +1,64 @@
+"""Abstract WorldInterface — the contract every game-world adapter must fulfil.
+
+Follows a Gymnasium-inspired pattern: observe → act → speak, with each
+method returning strongly-typed data structures.
+
+Any future engine (TES3MP, Luanti, Godot, …) plugs in by subclassing
+``WorldInterface`` and implementing the three methods.
+"""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+from infrastructure.world.types import ActionResult, CommandInput, PerceptionOutput
+
+
+class WorldInterface(ABC):
+    """Engine-agnostic base class for world adapters.
+
+    Subclasses must implement:
+        - ``observe()``  — gather structured perception from the world
+        - ``act()``      — dispatch a command and return the outcome
+        - ``speak()``    — send a message to an NPC / player / broadcast
+
+    Lifecycle hooks ``connect()`` and ``disconnect()`` are optional.
+    """
+
+    # -- lifecycle (optional overrides) ------------------------------------
+
+    def connect(self) -> None:
+        """Establish connection to the game world.
+
+        Default implementation is a no-op.  Override to open sockets,
+        authenticate, etc.
+        """
+
+    def disconnect(self) -> None:
+        """Tear down the connection.
+
+        Default implementation is a no-op.
+        """
+
+    @property
+    def is_connected(self) -> bool:
+        """Return ``True`` if the adapter has an active connection.
+
+        Default returns ``True``.  Override for adapters that maintain
+        persistent connections.
+        """
+        return True
+
+    # -- core contract (must implement) ------------------------------------
+
+    @abstractmethod
+    def observe(self) -> PerceptionOutput:
+        """Return a structured snapshot of the current world state."""
+
+    @abstractmethod
+    def act(self, command: CommandInput) -> ActionResult:
+        """Execute *command* in the world and return the result."""
+
+    @abstractmethod
+    def speak(self, message: str, target: str | None = None) -> None:
+        """Send *message* in the world, optionally directed at *target*."""