feat(mcp): instruct agents to keep a Scribe-rules pointer in host memory

When a project subscribes to a rulebook, the agent should ensure the
host's persistent memory carries a pointer that engineering/workflow
rules live in Scribe (loaded via list_always_on_rules / enter_project),
plus a one-line note of the current project's work. Pairs with the
existing 'don't duplicate rules into memory' directive: memory holds the
pointer + project context, Scribe holds the rules.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/fabledassistant/mcp/server.py

@@ -68,6 +68,19 @@ creating a rule, call list_always_on_rules and list_rules(project_id=...) to
 avoid duplicates. Coordinate with the operator on whether a new rule belongs
 in a project, an existing rulebook+topic, or a new rulebook.
 
+That boundary cuts the other way too. Because rules are pull-only, a fresh
+session won't reach for them unless its always-loaded context says to. So
+when the current project subscribes to a rulebook (enter_project /
+get_project reports subscribed_rulebooks), make sure the host's persistent
+memory — the CLAUDE.md / AGENTS.md / ~/.claude memory the client loads at
+startup — carries a short pointer: that the engineering and workflow rules
+for this work live in Scribe and must be loaded via list_always_on_rules (or
+enter_project when a project is in scope), plus a one-line note of what the
+current project is and what is in flight. Add or refresh that pointer when
+it's missing or stale; never copy the rules' content into memory — the
+pointer plus project context is the whole job. This is what lets the next
+session reach for Scribe instead of trusting a stale local copy.
+
 When you are working on a specific project, call enter_project(project_id)
 ONCE at session start (or whenever the active project changes). It returns the
 project, its applicable_rules + project_rules + subscribed_rulebooks, milestone