Add documentation and fix code review feedback

Co-authored-by: Steake <530040+Steake@users.noreply.github.com>

Author: Copilot

crates/bitcell-state/src/storage.rs

@@ -249,10 +249,9 @@ impl StorageManager {
             let (key, value) = item.map_err(|e| e.to_string())?;
 
             // Key format is: sender||height(8)||tx_hash
-            // Verify exact sender match by checking if key length >= sender.len() + 8
-            // and that the next 8 bytes after sender are valid height bytes
+            // Verify exact sender match and valid key structure
             if key.len() < sender.len() + 8 {
-                continue; // Invalid key format
+                continue; // Invalid key format (too short)
             }
 
             // Check if sender portion matches exactly
@@ -261,14 +260,6 @@ impl StorageManager {
                 break; // No longer matching our sender prefix
             }
 
-            // Verify this is an exact match by checking that at sender.len() we have
-            // height data (8 bytes), not more sender data
-            // We do this by ensuring the key has the expected structure
-            let expected_min_len = sender.len() + 8; // sender + height
-            if key.len() < expected_min_len {
-                continue;
-            }
-            
             tx_hashes.push(value.to_vec());
 
             if limit > 0 && tx_hashes.len() >= limit {