feat: Add --filters option to --get and parse filters early

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/args.rs

@@ -90,6 +90,10 @@ pub struct ItemArgs {
     #[arg(help_heading("Item Options"), short('M'), long, env("KEEP_META_PLUGINS"))]
     #[arg(help("Meta plugins to use when saving items"))]
     pub meta_plugins: Vec<String>,
+
+    #[arg(help_heading("Item Options"), long, env("KEEP_FILTERS"))]
+    #[arg(help("Filter string to apply to content when getting items"))]
+    pub filters: Option<String>,
 }