fix: allow mining directories without local mempalace.yaml

When no mempalace.yaml or mempal.yaml exists in the source directory,
return a default config (wing = directory name, room = general) instead
of calling sys.exit(1). This lets users mine any directory into their
palace without requiring init first.

Closes #14.

mempalace/miner.py

@@ -264,16 +264,28 @@ def load_config(project_dir: str) -> dict:
     """Load mempalace.yaml from project directory (falls back to mempal.yaml)."""
     import yaml
 
-    config_path = Path(project_dir).expanduser().resolve() / "mempalace.yaml"
+    resolved_project_dir = Path(project_dir).expanduser().resolve()
+    config_path = resolved_project_dir / "mempalace.yaml"
     if not config_path.exists():
         # Fallback to legacy name
-        legacy_path = Path(project_dir).expanduser().resolve() / "mempal.yaml"
+        legacy_path = resolved_project_dir / "mempal.yaml"
         if legacy_path.exists():
             config_path = legacy_path
         else:
-            print(f"ERROR: No mempalace.yaml found in {project_dir}")
-            print(f"Run: mempalace init {project_dir}")
-            sys.exit(1)
+            print(
+                f"  No mempalace.yaml found in {resolved_project_dir} "
+                "— using auto-detected defaults"
+            )
+            return {
+                "wing": resolved_project_dir.name,
+                "rooms": [
+                    {
+                        "name": "general",
+                        "description": "All project files",
+                        "keywords": ["general"],
+                    }
+                ],
+            }
     with open(config_path) as f:
         return yaml.safe_load(f)