docs(parsing): add package and symbol doc comments

Add godoc comments for all 62 exported symbols across 20 files in
config/parsing/: 23 MDKey constants, 35 Parse*/List/Default* functions,
3 TLS helpers, 1 Args struct with 7 fields, and the package doc.

config/parsing/bypass/parse.go

@@ -14,6 +14,9 @@ import (
 	"github.com/go-gost/x/registry"
 )
 
+// ParseBypass converts a BypassConfig into a bypass.Bypass. It resolves plugin
+// backends (HTTP or gRPC) when cfg.Plugin is set, or constructs an in-process
+// bypass with optional file, Redis, and HTTP hot-reload support.
 func ParseBypass(cfg *config.BypassConfig) bypass.Bypass {
 	if cfg == nil {
 		return nil
@@ -74,6 +77,8 @@ func ParseBypass(cfg *config.BypassConfig) bypass.Bypass {
 	return xbypass.NewBypass(opts...)
 }
 
+// List resolves one or more bypass names from the registry. It returns only
+// the bypasses that were found, skipping any that are not registered.
 func List(name string, names ...string) []bypass.Bypass {
 	var bypasses []bypass.Bypass
 	if bp := registry.BypassRegistry().Get(name); bp != nil {