fix: unify project path so path is always the local filesystem path

Cloud projects with bisync had a split-brain problem: `path` held a cloud
slug while the actual local directory lived in `local_sync_path`. This caused
`bm status` and file sync to fail for bisync'd cloud projects.

Changes:
- Config migration promotes `local_sync_path` → `path` for entries where
  `path` is a non-absolute cloud slug
- `ensure_project_paths_exists` skips cloud-only projects with slug paths
- `initialize_file_sync` and watch service now keep cloud projects that have
  an absolute local path (bisync copy) instead of skipping all cloud projects
- `sync-setup` and `project add --cloud --local-path` set both `path` and
  `local_sync_path` to the local directory
- `sync-setup` creates the project in the local DB for immediate MCP use
- `_get_sync_project` falls back from `local_sync_path` to `path`
- Config load errors now show user-friendly messages instead of stack traces

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: phernandez <paul@basicmachines.co>

src/basic_memory/cli/commands/project.py

@@ -285,9 +285,10 @@ def add_project(
             local_dir = Path(local_sync_path)
             local_dir.mkdir(parents=True, exist_ok=True)
 
-            # Update project entry with sync path
+            # Update project entry — path is always the local directory
             entry = config.projects.get(name)
             if entry:
+                entry.path = local_sync_path
                 entry.local_sync_path = local_sync_path
             else:
                 # Project may not be in local config yet (cloud-only add)