fix(discord): use correct slash command context type in AddApplicationCommands

The default AddApplicationCommands() registers ApplicationCommandService<ApplicationCommandContext>,
but our modules inherit ApplicationCommandModule<SlashCommandContext>. Because SlashCommandContext
does not inherit from ApplicationCommandContext in NetCord, AddModules(typeof(Program).Assembly)
failed to discover the modules, so /newsession, /listsessions, /reschedule were never published
to Discord. Only /ping worked because it uses the minimal API route.

Fix: specify AddApplicationCommands<SlashCommandInteraction, SlashCommandContext>() so the
service matches the module context type, allowing module discovery to succeed.

Bump version to 3.0.4.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/deploy.yml

@@ -6,7 +6,7 @@ on:
       - main 
 
 env:
-  VERSION: 3.0.3
+  VERSION: 3.0.4
 
 jobs:
   # ЧАСТЬ 1: Собираем образы и кладем в Gitea (чтобы делиться с ребятами)