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/digest.rs

@@ -20,7 +20,6 @@ struct DigestLevel {
     title: &'static str,
     period: &'static str,
     input_title: &'static str,
-    timeout: u64,
     child_name: Option<&'static str>, // None = journal (leaf), Some = child digest files
     /// Expand an arg into (canonical_label, dates covered).
     label_dates: fn(&str) -> Result<(String, Vec<String>), String>,
@@ -33,7 +32,6 @@ const DAILY: DigestLevel = DigestLevel {
     title: "Daily",
     period: "Date",
     input_title: "Journal entries",
-    timeout: 300,
     child_name: None,
     label_dates: |date| Ok((date.to_string(), vec![date.to_string()])),
     date_to_label: |date| Some(date.to_string()),
@@ -57,7 +55,6 @@ const WEEKLY: DigestLevel = DigestLevel {
     title: "Weekly",
     period: "Week",
     input_title: "Daily digests",
-    timeout: 300,
     child_name: Some("daily"),
     label_dates: |arg| {
         if !arg.contains('W') {
@@ -82,7 +79,6 @@ const MONTHLY: DigestLevel = DigestLevel {
     title: "Monthly",
     period: "Month",
     input_title: "Weekly digests",
-    timeout: 600,
     child_name: Some("weekly"),
     label_dates: |arg| {
         let (year, month) = if arg.len() <= 7 {