feat: add memory embedding cache

docs/concepts/memory.md

@@ -157,9 +157,28 @@ Local mode:
 ### What gets indexed (and when)
 
 - File type: Markdown only (`MEMORY.md`, `memory/**/*.md`).
-- Index storage: per-agent SQLite at `~/.clawdbot/state/memory/<agentId>.sqlite` (configurable via `agents.defaults.memorySearch.store.path`, supports `{agentId}` token).
-- Freshness: watcher on `MEMORY.md` + `memory/` marks the index dirty (debounce 1.5s). Sync runs on session start, on first search when dirty, and optionally on an interval. Reindex triggers when embedding model/provider or chunk sizes change.
-- Model changes: the index stores the embedding **model + provider + chunking params**. If any of those change, Clawdbot automatically resets and reindexes the entire store.
+- Index storage: per-agent SQLite at `~/.clawdbot/memory/<agentId>.sqlite` (configurable via `agents.defaults.memorySearch.store.path`, supports `{agentId}` token).
+- Freshness: watcher on `MEMORY.md` + `memory/` marks the index dirty (debounce 1.5s). Sync runs on session start, on first search when dirty, and optionally on an interval.
+- Reindex triggers: the index stores the embedding **provider/model + endpoint fingerprint + chunking params**. If any of those change, Clawdbot automatically resets and reindexes the entire store.
+
+### Embedding cache
+
+Clawdbot can cache **chunk embeddings** in SQLite so reindexing and frequent updates (especially session transcripts) don't re-embed unchanged text.
+
+Config:
+
+```json5
+agents: {
+  defaults: {
+    memorySearch: {
+      cache: {
+        enabled: true,
+        maxEntries: 50000
+      }
+    }
+  }
+}
+```
 
 ### Session memory search (experimental)