docs: add ReMe2 architecture design documentation
- Add comprehensive design document (reme2.md) detailing the
three-layer architecture (L1/L2/L3) for the vault system
- Document new protocols for folder notes and memory management
- Specify interface contracts for memory_* and vault_* tools
- Outline implementation phases from current state to target
refactor: fix typo in personal retriever class
- Correct spelling error: 'retri eved_nodes' -> 'retrieved_nodes'
in PersonalRetriever.result assignment
chore: update gitignore with vault-related patterns
- Add '/vault' to ignore vault directory
- Add '/reme-plugin' to ignore plugin files
- Add '/reme2/vault' to ignore new vault implementation
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- Remove abstract methods from base component start/close
- Update BaseJob to remove name parameter and simplify initialization
- Change file modification time field from mtime_ms to modified_time in seconds
- Add type checking imports and improve typing annotations
- Implement LocalFileStore with JSONL persistence for file chunks
- Add MdFileParser with markdown and frontmatter support
- Simplify HttpClient call method with proper kwargs handling
- Remove unused ReMe class methods and create backup version
- Update StreamJob to use step_components instead of steps attribute
