docs: clarify memory system is SF-internal, not MCP-exposed

Add architecture decision: Memory is not exposed as MCP server.

- SF is an MCP client only (consumes external MCP tools)
- Memory is internal SF infrastructure (uses SQLite, fire-and-forget async)
- Memory exposed as SF tools only (capture, query, graph)
- No external MCP exposure needed (memory is autonomous learning, not a service)

This keeps SF's learning system private and prevents:
- External memory pollution
- Uncontrolled confidence scoring
- Inconsistent learning patterns
- Loss of autonomy (memory decisions stay internal)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docs/dev/MEMORY-SYSTEM-ARCHITECTURE.md

@@ -513,6 +513,23 @@ All memory operations follow the **fire-and-forget pattern**:
 
 ---
 
+## Architecture Decision: SF Tools, Not MCP
+
+**Memory is NOT exposed as MCP server.**
+
+- **SF is an MCP *client* only** — SF consumes MCP tools from external services
+- **Memory is internal SF infrastructure** — uses SQLite (Node 24 native)
+- **Memory exported as SF tools** — LLM agents within SF call memory functions
+- **No external exposure** — Memory system is not a service; it's SF's autonomous learning mechanism
+
+This keeps memory **private to SF** and prevents:
+- External memory pollution
+- Uncontrolled confidence scoring
+- Inconsistent learning patterns
+- Loss of autonomy (memory decisions stay internal)
+
+---
+
 ## See Also
 
 - **ADR-0075:** UOK Gate Architecture
@@ -520,3 +537,4 @@ All memory operations follow the **fire-and-forget pattern**:
 - `docs/dev/UOK-SELF-EVOLUTION.md` — How SF learns
 - `src/resources/extensions/sf/uok/unit-runtime.js` — Unit recording
 - `src/resources/extensions/sf/auto-dispatch.js` — Dispatch ranking
+- `src/resources/extensions/sf/tools/memory-tools.js` — SF tool executors