tighten module interfaces: explicit re-exports, private helpers, inline dedup

- Replace `pub use types::*` in store/mod.rs with explicit re-export list
- Make transcript_dedup_key private in agents/enrich.rs (only used internally)
- Inline duplicated projects_dir() helper in agents/knowledge.rs and daemon.rs

poc-memory/src/agents/enrich.rs

@@ -22,7 +22,7 @@ use crate::util::parse_timestamp_to_epoch;
 
 /// Compute the store dedup key for a transcript file.
 /// This is the same key experience_mine uses to mark a transcript as mined.
-pub fn transcript_dedup_key(path: &str) -> Result<String, String> {
+fn transcript_dedup_key(path: &str) -> Result<String, String> {
     let bytes = fs::read(path).map_err(|e| format!("read {}: {}", path, e))?;
     let mut hasher = DefaultHasher::new();
     bytes.hash(&mut hasher);