fix: Cache purge pattern - use sql-cli: instead of sql_cli:

The cache keys are stored with hyphen (sql-cli:web:...) but purge was
searching for underscore pattern (sql_cli:*), causing 0 entries to be found.

Fixed pattern to match actual key format: sql-cli:*

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: TimelordUK

src/redis_cache_module/redis_cache.rs

@@ -268,7 +268,7 @@ impl RedisCache {
     }
 
     /// Check cache statistics
-    /// Purge all cache entries (delete all keys matching sql_cli:* pattern)
+    /// Purge all cache entries (delete all keys matching sql-cli:* pattern)
     pub fn purge_all(&mut self) -> Result<usize, String> {
         if !self.enabled {
             return Err("Cache not enabled".to_string());
@@ -277,7 +277,7 @@ impl RedisCache {
         let conn = self.connection.as_mut().ok_or("No connection")?;
 
         // Scan for all keys matching our prefix
-        let pattern = "sql_cli:*";
+        let pattern = "sql-cli:*";
         let keys: Vec<String> = redis::cmd("KEYS")
             .arg(pattern)
             .query(conn)