Initial commit: NexusOS project + desktop theme baseline

Captures the known-good state after theme consolidation and
consistency reconciliation:
- NexusOS GTK/xfwm4/icon theme assets (assets/themes, management/Mint-Y-Nexus)
- Tightened right-click menus, visible separators, no menu icons
- assets/themes/install-theme.sh: idempotent restore of all wiring
  (symlinks, xfconf xsettings+xfwm4, GTK 3/4 settings.ini)
- .gitignore excludes venv/ollama/models/runtime/db

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

synapse/playbook_manager.py

@@ -0,0 +1,42 @@
+import threading
+from typing import List
+from .playbooks.store import playbook_store, PlaybookItem
+
+
+class PlaybookManager:
+    _lock = threading.Lock()
+
+    @classmethod
+    def _all(cls) -> List[PlaybookItem]:
+        """Return all playbooks sorted by order (position 0 is always main)."""
+        return playbook_store.all_playbooks()
+
+    @classmethod
+    def get_main_playbook(cls) -> PlaybookItem | None:
+        playbooks = cls._all()
+        return playbooks[0] if playbooks else None
+
+    @classmethod
+    def get_context_playbooks(cls) -> List[PlaybookItem]:
+        """All playbooks after the first — injected as reference context."""
+        playbooks = cls._all()
+        return playbooks[1:] if len(playbooks) > 1 else []
+
+    @classmethod
+    def get_system_prompt(cls) -> str:
+        playbook = cls.get_main_playbook()
+        return getattr(playbook, "instructions", "") or "" if playbook else ""
+
+    @classmethod
+    def render_prompt(cls, user_message: str, variables: dict | None = None) -> str:
+        if not variables:
+            return user_message
+        result = user_message
+        for key, value in variables.items():
+            result = result.replace(f"{{{{{key}}}}}", str(value))
+        return result
+
+    # Keep old name as alias so nothing else breaks
+    @classmethod
+    def get_active_playbook(cls) -> PlaybookItem | None:
+        return cls.get_main_playbook()