Add snippet/command library with CRUD and send-to-session

Full command snippet library for saving and sending reusable commands:

Backend:
- SQLite migration 003 creates snippets table
- Snippet model with name, command, description, folder, tags
- Store CRUD methods and API endpoints

Frontend:
- SnippetLibrary class with searchable list + detail/editor split view
- Create, edit, delete snippets in modal dialog
- 'Send to Session' button writes command to active terminal
- 'Send Snippet' option in terminal right-click context menu
- Ctrl+Shift+S keyboard shortcut to open library

frontend/wailsjs/go/api/Service.js

@@ -30,6 +30,10 @@ export function CreateProfile(arg1) {
   return window['go']['api']['Service']['CreateProfile'](arg1);
 }
 
+export function CreateSnippet(arg1) {
+  return window['go']['api']['Service']['CreateSnippet'](arg1);
+}
+
 export function DeleteKnownHost(arg1) {
   return window['go']['api']['Service']['DeleteKnownHost'](arg1);
 }
@@ -46,6 +50,10 @@ export function DeleteRecording(arg1) {
   return window['go']['api']['Service']['DeleteRecording'](arg1);
 }
 
+export function DeleteSnippet(arg1) {
+  return window['go']['api']['Service']['DeleteSnippet'](arg1);
+}
+
 export function DisconnectSession(arg1) {
   return window['go']['api']['Service']['DisconnectSession'](arg1);
 }
@@ -150,6 +158,10 @@ export function ListSessions() {
   return window['go']['api']['Service']['ListSessions']();
 }
 
+export function ListSnippets() {
+  return window['go']['api']['Service']['ListSnippets']();
+}
+
 export function LockSecretStore() {
   return window['go']['api']['Service']['LockSecretStore']();
 }
@@ -274,6 +286,10 @@ export function UpdateProfile(arg1) {
   return window['go']['api']['Service']['UpdateProfile'](arg1);
 }
 
+export function UpdateSnippet(arg1) {
+  return window['go']['api']['Service']['UpdateSnippet'](arg1);
+}
+
 export function WriteSession(arg1, arg2) {
   return window['go']['api']['Service']['WriteSession'](arg1, arg2);
 }