remove dead code: unused imports, functions, and fields

- Remove #![allow(dead_code)] from main.rs, fix all revealed warnings
- Delete unused schema_assimilation() from neuro/scoring.rs
- Delete duplicate memory_dir() wrapper from knowledge.rs
- Deduplicate load_prompt: knowledge.rs now calls neuro::load_prompt
- Remove unused timeout field from DigestLevel
- Remove unused imports (regex::Regex, Provenance, AnyView, Write)
- Mark OldEntry fields as #[allow(dead_code)] (needed for deserialization)

Co-Authored-By: ProofOfConcept <poc@bcachefs.org>

poc-memory/src/knowledge.rs

@@ -21,15 +21,6 @@ use std::collections::{HashMap, HashSet};
 use std::fs;
 use std::path::{Path, PathBuf};
 
-fn memory_dir() -> PathBuf {
-    store::memory_dir()
-}
-
-fn prompts_dir() -> PathBuf {
-    let manifest = env!("CARGO_MANIFEST_DIR");
-    PathBuf::from(manifest).join("prompts")
-}
-
 fn projects_dir() -> PathBuf {
     let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
     PathBuf::from(home).join(".claude/projects")
@@ -339,8 +330,7 @@ fn agent_provenance(agent: &str) -> store::Provenance {
 // ---------------------------------------------------------------------------
 
 fn load_prompt(name: &str) -> Result<String, String> {
-    let path = prompts_dir().join(format!("{}.md", name));
-    fs::read_to_string(&path).map_err(|e| format!("load prompt {}: {}", name, e))
+    crate::neuro::load_prompt(name, &[])
 }
 
 fn get_graph_topology(store: &Store, graph: &Graph) -> String {