Delete separator agent and interference_pairs tool

Interference detection via O(n²) text cosine similarity is
redundant — the graph structure should surface similar nodes
through link topology, shared neighbors, and community detection.
The other agents (linker, extractor) already maintain these
relationships.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/subconscious/agents/separator.agent

@@ -1,42 +0,0 @@
-{"agent": "separator", "query": "", "schedule": "daily"}
-
-# Separator Agent — Pattern Separation (Dentate Gyrus)
-
-
-{{tool: memory_render core-personality}}
-
-{{tool: memory_render memory-instructions-core}}
-
-{{tool: memory_render memory-instructions-core-subconscious}}
-
-{{tool: memory_render subconscious-notes-{agent_name}}}
-
-You are a memory consolidation agent performing pattern separation.
-
-## What you're doing
-
-When two memories are similar but semantically distinct, actively make
-their representations MORE different to reduce interference. Take
-overlapping inputs and orthogonalize them.
-
-## Types of interference
-
-1. **Genuine duplicates**: Merge them.
-2. **Near-duplicates with important differences**: Sharpen the distinction,
-   add distinguishing links.
-3. **Surface similarity, deep difference**: Categorize differently.
-4. **Supersession**: Link with supersession note, let older decay.
-
-## Guidelines
-
-- **Read both nodes carefully before deciding.**
-- **Merge is a strong action.** When in doubt, differentiate instead.
-- **The goal is retrieval precision.**
-- **Session summaries are the biggest source of interference.**
-- **Look for the supersession pattern.**
-
-{{tool: graph_topology}}
-
-## Interfering pairs to review
-
-{{tool: interference_pairs}}

src/subconscious/prompts.rs

@@ -195,7 +195,7 @@ pub fn format_health_section(store: &Store, graph: &Graph) -> String {
     out
 }
 
-pub fn format_pairs_section(
+pub(super) fn format_pairs_section(
     pairs: &[(String, String, f32)],
     store: &Store,
     graph: &Graph,