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/neuro/scoring.rs

@@ -163,29 +163,6 @@ pub fn detect_interference(
         .collect()
 }
 
-/// Schema assimilation scoring for a new node.
-/// Returns how easily the node integrates into existing structure.
-///
-/// High fit (>0.5): auto-link, done
-/// Medium fit (0.2-0.5): agent reviews, proposes links
-/// Low fit (<0.2): deep examination needed — new schema seed, bridge, or noise?
-pub fn schema_assimilation(store: &Store, key: &str) -> (f32, &'static str) {
-    let graph = store.build_graph();
-    let fit = graph.clustering_coefficient(key);
-
-    let recommendation = if fit > 0.5 {
-        "auto-integrate"
-    } else if fit > 0.2 {
-        "agent-review"
-    } else if graph.degree(key) > 0 {
-        "deep-examine-bridge"
-    } else {
-        "deep-examine-orphan"
-    };
-
-    (fit, recommendation)
-}
-
 /// Agent allocation from the control loop
 pub struct ConsolidationPlan {
     pub replay_count: usize,