fix: initialize magic cookie with mime type and encoding flags

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/meta_plugin/magic.rs

@@ -104,8 +104,8 @@ impl MetaPlugin for MagicFileMetaPlugin {
         // Store raw pointer to connection - unsafe but necessary for this design
         self.conn = Some(conn as *const _ as *mut Connection);
         
-        // Initialize magic cookie
-        let cookie = Cookie::open(CookieFlags::empty())
+        // Initialize magic cookie with flags for comprehensive detection
+        let cookie = Cookie::open(CookieFlags::MIME_TYPE | CookieFlags::MIME_ENCODING)
             .map_err(|e| anyhow::anyhow!("Failed to open magic cookie: {}", e))?;
         cookie.load(&[] as &[&str])
             .map_err(|e| anyhow::anyhow!("Failed to load magic database: {}", e))?;