The command now supports reopening existing indexes instead of failing when the output file exists. Control flow branches between opening an existing index and constructing a new one, moving configuration setup exclusively to the creation path. Directory existence is enforced upfront with proper I/O error propagation. The --force flag retains its original semantics by removing the target directory before proceeding with a fresh build.
Update Cargo manifests, dependency paths, and Rust imports across the workspace to reflect the `obikpartitionner` to `obikpartition` rename. Synchronize architecture and implementation documentation with the new module structure. Fix minor syntax issues in test assertions to ensure compilation compatibility. No behavioral or API changes are introduced.