Add "disable_by_default" flag for plugins

Signed-off-by: Hadi <112569860+anotherhadi@users.noreply.github.com>

docs/plugins.md

@@ -18,6 +18,7 @@ Plugin = {
   name               = "My Plugin",
   description        = "What this plugin does.",
   priority           = 0,     -- higher = runs before other plugins (default: 0)
+  disable_by_default = true,  -- if true, plugin starts disabled on first load (default: false)
 
   -- Declare which hooks you use and whether they are synchronous (default: false).
   -- on_config and on_quit are always sync and do not need to be declared here.

internal/plugins/manager.go

@@ -117,6 +117,10 @@ func (m *Manager) loadPlugin(path string) (*Plugin, error) {
 		p.Priority = int(n)
 	}
 
+	if pluginTable.RawGetString("disable_by_default") == lua.LTrue {
+		p.Enabled = false
+	}
+
 	// Hooks configurable via the Plugin table (sync field).
 	configurableHooks := map[string]bool{
 		"on_start":         false, // async by default

plugins/ip_filter.lua

@@ -10,6 +10,7 @@ Checks that the proxy's outbound IP is in an allowed list on startup.
 - if no IPs are configured, the check is skipped
   ]],
   on_start = { sync = false },
+  disable_by_default = true,
 }
 
 local whitelist = {}