Fix all lint issues and update AGENTS.md workflow rules

- Fix stuttering type names (e.g. config.ConfigParams → config.Params)
- Add doc comments to all exported types/functions/methods
- Add package doc comments to all packages
- Fix JSON tags to camelCase
- Extract magic numbers to constants
- Add blank lines per nlreturn/wsl_v5 rules
- Use errors.Is() for error comparison
- Unexport NewLoggingResponseWriter (not used externally)
- Replace for-range on ctx.Done() with channel receive
- Rename unused parameters to _
- AGENTS.md: all changes via feature branches, no direct main commits

internal/config/config.go

@@ -2,6 +2,7 @@
 package config
 
 import (
+	"errors"
 	"log/slog"
 
 	"git.eeqj.de/sneak/chat/internal/globals"
@@ -12,8 +13,8 @@ import (
 	_ "github.com/joho/godotenv/autoload" // loads .env file
 )
 
-// ConfigParams defines the dependencies for creating a Config.
-type ConfigParams struct {
+// Params defines the dependencies for creating a Config.
+type Params struct {
 	fx.In
 
 	Globals *globals.Globals
@@ -35,12 +36,12 @@ type Config struct {
 	MOTD            string
 	ServerName      string
 	FederationKey   string
-	params          *ConfigParams
+	params          *Params
 	log             *slog.Logger
 }
 
 // New creates a new Config by reading from files and environment variables.
-func New(_ fx.Lifecycle, params ConfigParams) (*Config, error) {
+func New(_ fx.Lifecycle, params Params) (*Config, error) {
 	log := params.Logger.Get()
 	name := params.Globals.Appname
 
@@ -66,7 +67,8 @@ func New(_ fx.Lifecycle, params ConfigParams) (*Config, error) {
 
 	err := viper.ReadInConfig()
 	if err != nil {
-		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
+		var notFound viper.ConfigFileNotFoundError
+		if !errors.As(err, &notFound) {
 			log.Error("config file malformed", "error", err)
 			panic(err)
 		}