fix: replace std::sync::Mutex with parking_lot::Mutex (#350)

Merges #422

src/config/schema.rs

@@ -743,6 +743,28 @@ pub struct MemoryConfig {
     /// Max tokens per chunk for document splitting
     #[serde(default = "default_chunk_size")]
     pub chunk_max_tokens: usize,
+
+    // ── Response Cache (saves tokens on repeated prompts) ──────
+    /// Enable LLM response caching to avoid paying for duplicate prompts
+    #[serde(default)]
+    pub response_cache_enabled: bool,
+    /// TTL in minutes for cached responses (default: 60)
+    #[serde(default = "default_response_cache_ttl")]
+    pub response_cache_ttl_minutes: u32,
+    /// Max number of cached responses before LRU eviction (default: 5000)
+    #[serde(default = "default_response_cache_max")]
+    pub response_cache_max_entries: usize,
+
+    // ── Memory Snapshot (soul backup to Markdown) ─────────────
+    /// Enable periodic export of core memories to MEMORY_SNAPSHOT.md
+    #[serde(default)]
+    pub snapshot_enabled: bool,
+    /// Run snapshot during hygiene passes (heartbeat-driven)
+    #[serde(default)]
+    pub snapshot_on_hygiene: bool,
+    /// Auto-hydrate from MEMORY_SNAPSHOT.md when brain.db is missing
+    #[serde(default = "default_true")]
+    pub auto_hydrate: bool,
 }
 
 fn default_embedding_provider() -> String {
@@ -778,6 +800,12 @@ fn default_cache_size() -> usize {
 fn default_chunk_size() -> usize {
     512
 }
+fn default_response_cache_ttl() -> u32 {
+    60
+}
+fn default_response_cache_max() -> usize {
+    5_000
+}
 
 impl Default for MemoryConfig {
     fn default() -> Self {
@@ -795,6 +823,12 @@ impl Default for MemoryConfig {
             keyword_weight: default_keyword_weight(),
             embedding_cache_size: default_cache_size(),
             chunk_max_tokens: default_chunk_size(),
+            response_cache_enabled: false,
+            response_cache_ttl_minutes: default_response_cache_ttl(),
+            response_cache_max_entries: default_response_cache_max(),
+            snapshot_enabled: false,
+            snapshot_on_hygiene: false,
+            auto_hydrate: true,
         }
     }
 }