fix: resolve case-insensitive project switching database lookup issue

Fix project switching bug where case-insensitive matching worked but
caused database lookup failures for subsequent operations.

**Problem:**
- switch_project('personal') succeeded (case-insensitive matching)
- get_current_project() failed with 'Project personal not found'
- Session stored user input case instead of canonical database name

**Solution:**
- Find project by permalink (case-insensitive) in switch_project
- Store canonical project name from database in session
- Use canonical name for all API calls and responses

**Test Coverage:**
- Added comprehensive case-insensitive project switching tests
- Added tests for case preservation in project listings
- Added tests for session state consistency after case switching
- Added error handling tests for non-existent projects

**Files Changed:**
- src/basic_memory/mcp/tools/project_management.py: Fixed switch_project logic
- test-int/mcp/test_project_management_integration.py: Added test coverage

**Test Cases Now Passing:**
- ✅ switch_project('personal') → finds 'Personal' project
- ✅ get_current_project() → works with canonical name
- ✅ Project summary shows stats correctly
- ✅ Case-insensitive matching for all case variations
- ✅ Error handling for non-existent projects

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/basic_memory/config.py

@@ -256,11 +256,14 @@ def get_project_config(project_name: Optional[str] = None) -> ProjectConfig:
     # the config contains a dict[str,str] of project names and absolute paths
     assert actual_project_name is not None, "actual_project_name cannot be None"
 
-    project_path = app_config.projects.get(actual_project_name)
-    if not project_path:  # pragma: no cover
-        raise ValueError(f"Project '{actual_project_name}' not found")
+    project_permalink = generate_permalink(actual_project_name)
 
-    return ProjectConfig(name=actual_project_name, home=Path(project_path))
+    for name, path in app_config.projects.items():
+        if project_permalink == generate_permalink(name):
+            return ProjectConfig(name=name, home=Path(path))
+
+    # otherwise raise error
+    raise ValueError(f"Project '{actual_project_name}' not found")
 
 
 # Create config manager
@@ -335,4 +338,4 @@ def setup_basic_memory_logging():  # pragma: no cover
 
 
 # Set up logging
-setup_basic_memory_logging()
+setup_basic_memory_logging()