Add exact KV memory with persona overlays and param priority.

Canonical defaults live in exact.json (UI fills empties without an LLM call); chat session overrides beat file defaults until clear/persona change.

Co-authored-by: Cursor <cursoragent@cursor.com>

Config/_base/skills/memory.json

@@ -1,6 +1,6 @@
 {
   "id": "memory",
-  "title": "Vector memory",
+  "title": "Exact + vector memory",
   "default": true,
   "prompt_file": "memory.md"
 }