v3.6.21

Fixed

• RAM Guardian now performs real cache eviction under memory pressure (#300): Previously, the memory_guard eviction callback only called jemalloc_purge(), which returns already-freed pages to the OS but never evicts actual data (SessionCache, BM25 index, etc.). Now a new EvictionOrchestrator bridges the RSS-based memory guardian to the HomeostasisController, enabling 5-stage graduated eviction: trim compressed outputs → evict probationary entries → unload BM25 index → evict protected entries → emergency full cache clear.
• jemalloc_purge() error handling: Previously swallowed errors with let _ =. Now logs failures via tracing::debug for diagnosability.
• is_under_pressure() no longer expensive in hot loops: Was calling MemorySnapshot::capture() (which does Config::load() + syscalls) on every invocation in BM25/graph index builders. Now reads a cached AtomicU8 flag set by the guardian thread — O(1) with zero allocations.

Added

• EvictionOrchestrator (core/eviction_orchestrator.rs): New module connecting memory_guard (RSS monitoring) to HomeostasisController (graduated eviction). Holds Arc references to SessionCache and SharedBm25Cache, executes eviction actions with non-blocking try_read/try_write to avoid stalling the guardian thread.
• SessionCache eviction methods: trim_compressed_outputs(), evict_probationary(), evict_to_budget(), approximate_bytes(), trim_shared_blocks() — enable fine-grained memory reclamation under pressure.
• BM25 cache management: bm25_cache::unload() drops the cached index (rebuilt on next search), bm25_cache::memory_usage() reports current heap usage.
• Doctor pressure hints: RAM Guardian check now shows the active pressure level and recommends memory_profile = "low" or increasing max_ram_percent when under pressure.

Upgrade

lean-ctx update                 # recommended (auto-downloads + refreshes shell hooks)
cargo install lean-ctx          # or
npm update -g lean-ctx-bin      # or
brew upgrade lean-ctx

Note: After upgrading via cargo/npm/brew, run lean-ctx setup to refresh shell aliases. lean-ctx update does this automatically.

Full Changelog: v3.6.21...v3.6.21