feat: introduce BASIC_MEMORY_PROJECT_ROOT for path constraints (#334)

Signed-off-by: phernandez <paul@basicmachines.co>

src/basic_memory/services/project_service.py

@@ -99,13 +99,12 @@ class ProjectService:
         Raises:
             ValueError: If the project already exists
         """
-        # in cloud mode, don't allow arbitrary paths.
-        if self.config_manager.config.cloud_mode_enabled:
-            basic_memory_home = os.getenv("BASIC_MEMORY_HOME")
-            assert basic_memory_home is not None
-            base_path = Path(basic_memory_home)
+        # If project_root is set, constrain all projects to that directory
+        project_root = self.config_manager.config.project_root
+        if project_root:
+            base_path = Path(project_root)
 
-            # Sanitize the input path for cloud mode
+            # Sanitize the input path
             # Strip leading slashes, home directory references, and parent directory references
             clean_path = path.lstrip("/").replace("~/", "").replace("~", "")
 
@@ -116,13 +115,14 @@ class ProjectService:
                     path_parts.append(part)
             clean_path = "/".join(path_parts) if path_parts else ""
 
-            # Construct path relative to BASIC_MEMORY_HOME
+            # Construct path relative to project_root
             resolved_path = (base_path / clean_path).resolve().as_posix()
 
-            # Verify the resolved path is actually under BASIC_MEMORY_HOME
+            # Verify the resolved path is actually under project_root
             if not resolved_path.startswith(base_path.resolve().as_posix()):
                 raise ValueError(
-                    f"Cloud mode requires projects under {basic_memory_home}. Invalid path: {path}"
+                    f"BASIC_MEMORY_PROJECT_ROOT is set to {project_root}. "
+                    f"All projects must be created under this directory. Invalid path: {path}"
                 )
         else:
             resolved_path = Path(os.path.abspath(os.path.expanduser(path))).as_posix()