feat: add join form

config/config.exs

@@ -93,6 +93,9 @@ config :mv, Mv.Mailer, adapter: Swoosh.Adapters.Local
 # user confirmation, password reset). Override in config/runtime.exs from ENV.
 config :mv, :mail_from, {"Mila", "noreply@example.com"}
 
+# Join form rate limiting (Hammer). scale_ms: window in ms, limit: max submits per window per IP.
+config :mv, :join_rate_limit, scale_ms: 60_000, limit: 10
+
 # Configure esbuild (the version is required)
 config :esbuild,
   version: "0.17.11",

config/test.exs

@@ -55,3 +55,6 @@ config :mv, :default_locale, "en"
 # Enable SQL Sandbox for async LiveView tests
 # This flag controls sync vs async behavior in CycleGenerator after_action hooks
 config :mv, :sql_sandbox, true
+
+# Join form rate limit: low limit so tests can trigger rate limiting (e.g. 2 per minute)
+config :mv, :join_rate_limit, scale_ms: 60_000, limit: 2