v1.5.3 — Improved cache invalidation instructions

Improved MCP instructions for context compaction and session resets.

The LLM is now explicitly instructed to use fresh=true on ctx_read after context compaction, session resets, or whenever it sees a cache-hit but no longer has the file content in its context. Previously, instructions only covered the subagent use case.

Install: cargo install lean-ctx or brew install yvgude/lean-ctx/lean-ctx