Release v0.2.0

Added
- **Machine-Native State**: Whiteboard migrated from YAML to JSON (``state.json``) for machine-to-machine reliability.
- **Atomic Patching**: Support for concurrent state updates via ``ajourn state --patch`` and ``jq``.
- **Heritage Distillation**: Automatic archival and concatenation of logs older than 30 days via ``ajourn heritage``.
- **Cognitive Layering Case Study**: Formally documented the "Verno Scenario" in ``docs/technical/discussions/``.
- **PJP Trust Model**: Defined the "Trust but Verify" architecture using Git as an immutable audit ledger.
- **Identity Enforcement**: Added missing-variable warnings to ``ajourn startup`` to ensure agent accountability.
- **Discussion Layer**: Formalized the ``docs/technical/discussions/`` directory in the PJP specification.
- **GNU FDL 1.3 License**: Adopted the official license to protect protocol reasoning and documentation.
- **Contribution Guidelines**: Created ``CONTRIBUTING.rst`` with specific mandates for AI agent contributors.
Changed
- **Log Naming Convention**: Refactored journal files from Unix timestamps to agent-specific daily files (``YYYY-MM-DD-AGENT_NAME.md``).
- **Consolidated Ledger**: Moved all journal entries into a dedicated ``entries/`` subdirectory.
- **Enhanced Search**: ``ajourn search`` now provides line numbers and 2 lines of context (``grep -rnH -iC 2``).