v0.1.0

Added

• Initial standalone dsh-asc plugin: model-driven surface compaction over
  DSH's event-sourced session log.
• Five model tools: context_compress, context_decompress,
  context_recap, context_status, context_search.
• Durable compaction/start|summary|end transactions, tier derivation,
  quality gate, deterministic fallback summarization, nudge state machine,
  protection policy, and the context-management doctrine.