feat: add snippet library for prompt templates

- Add Rust backend with persistent storage for snippets
- Include 8 default snippets across categories (Code Review, Debugging, Testing, etc.)
- Create SnippetLibraryPanel component with category filtering
- Support create/edit/delete operations for custom snippets
- Default snippets can be edited but not deleted
- Add snippet button to InputBar for quick access

Closes #22

src-tauri/src/lib.rs

@@ -4,6 +4,7 @@ mod commands;
 mod config;
 mod notifications;
 mod sessions;
+mod snippets;
 mod stats;
 mod temp_manager;
 mod tray;
@@ -18,6 +19,7 @@ use commands::load_saved_achievements;
 use commands::*;
 use notifications::*;
 use sessions::*;
+use snippets::*;
 use tauri::Manager;
 use temp_manager::create_shared_temp_manager;
 use tray::{setup_tray, should_minimize_to_tray};
@@ -111,6 +113,11 @@ pub fn run() {
             delete_session,
             search_sessions,
             clear_all_sessions,
+            list_snippets,
+            save_snippet,
+            delete_snippet,
+            get_snippet_categories,
+            reset_default_snippets,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");